Surgical instruments with dual spherical articulation joint arrangements

ABSTRACT

Surgical instruments that have articulation joints that include a proximal joint member that defines a proximal face that defines a proximal apex and a distal joint member that defines a distal apex. A linkage assembly retains the proximal apex in rolling inter-engagement with the distal apex. The linkage assembly includes a first link and a second link that are coupled to the proximal joint member for pivotal travel relative thereto about a first proximal pivot axis a second proximal pivot axis. The first link and second link are coupled to the distal joint member for pivotal travel relative thereto about a first distal pivot axis and a second distal pivot axis.

CROSS-REFERENCE TO RELATED APPLICATIONS

This non-provisional application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application Ser. No. 63/057,430,entitled SURGICAL INSTRUMENTS WITH TORSION SPINE DRIVE ARRANGEMENTS,filed Jul. 28, 2020, of U.S. Provisional Patent Application Ser. No.63/057,432, entitled ARTICULATION JOINT ARRANGEMENTS FOR SURGICALINSTRUMENTS, filed Jul. 28, 2020, the disclosures of which areincorporated by reference herein in their entireties.

BACKGROUND

The present invention relates to surgical instruments and, in variousarrangements, to surgical stapling and cutting instruments and staplecartridges for use therewith that are designed to staple and cut tissue.The surgical instruments may be configured for use in open surgicalprocedures, but have applications in other types of surgery, such aslaparoscopic, endoscopic, and robotic-assisted procedures and mayinclude end effectors that are articulatable relative to a shaft portionof the instrument to facilitate precise positioning within a patient.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the various aspects are set forth withparticularity in the appended claims. The described aspects, however,both as to organization and methods of operation, may be best understoodby reference to the following description, taken in conjunction with theaccompanying drawings in which:

FIG. 1 is a perspective view of a surgical end effector portion of asurgical instrument in accordance with at least one aspect of thepresent disclosure;

FIG. 2 is a side view of the surgical end effector portion instrument ofFIG. 1 in a closed orientation;

FIG. 3 is an end view of the surgical end effector of FIG. 2;

FIG. 4 is a top view of the surgical end effector of FIG. 2;

FIG. 5 is an exploded assembly view of a portion of the surgicalinstrument of FIG. 1;

FIG. 6 is an exploded assembly view of an elongate shaft assembly of thesurgical instrument of FIG. 1;

FIG. 7 is another exploded assembly view of the elongate shaft assemblyof FIG. 6;

FIG. 8 is an exploded assembly view of a firing system and a rotarydrive system according to at least one aspect of the present disclosure;

FIG. 9 is a side view of a firing member and upper and lower flexiblespine assemblies of the firing system in engagement with a rotary drivescrew of the rotary drive system of FIG. 8;

FIG. 10 is a cross-sectional view of the firing member and upper andlower flexible spine assemblies of FIG. 9;

FIG. 11 is a side elevational view of the firing member and upper andlower flexible spine assemblies in engagement with the rotary drivescrew of FIG. 9;

FIG. 12 is a cross-sectional end view of the surgical end effector ofFIG. 4 taken along line 12-12 in FIG. 4;

FIG. 13 is an exploded perspective view of two adjacent upper vertebramembers of the upper flexible spine assembly of FIG. 10;

FIG. 14 is an exploded perspective view of two adjacent lower vertebramembers of the lower flexible spine assembly of FIG. 10;

FIG. 15 is a top view of a firing member and upper and lower flexiblespine assemblies in engagement with the rotary drive screw of FIG. 9;

FIG. 16 is a perspective view of a CV drive shaft assembly of the rotarydrive system of FIG. 8 in an articulated orientation;

FIG. 17 is a perspective view of the firing system of FIG. 8 in drivingengagement with the CV drive shaft assembly of FIG. 16 in accordancewith at least one aspect of the present disclosure;

FIG. 18 is a perspective view of a drive joint of the CV drive shaftassembly of FIG. 16;

FIG. 19 is a cross-sectional view of a portion of the surgicalinstrument of FIG. 4 taken along line 19-19 in FIG. 4;

FIG. 20 is a partial perspective view of a proximal end portion of thesurgical end effector and portions of the firing system and the rotarydrive system of the surgical instrument of FIG. 1;

FIG. 21 is a perspective view of the rotary drive system of the surgicalinstrument of FIG. 1 in driving engagement with the firing systemthereof in accordance with at least one aspect of the presentdisclosure;

FIG. 22 is an exploded perspective view of the rotary drive screw andthrust bearing arrangement of the firing system of FIG. 21;

FIG. 23 is a side view of the rotary drive screw of FIG. 22;

FIG. 24 is a partial cross-sectional side view of a portion of the lowerflexible spine assembly and a portion of the firing member of FIG. 21 indriving engagement with a portion of the rotary drive screw;

FIG. 25 is a perspective view of the firing member in a home or startingposition within the surgical end effector of the surgical instrument ofFIG. 1;

FIG. 26 is a side view illustrating the upper flexible spine assemblyand the lower flexible spine assembly of FIG. 21 in driving engagementwith the rotary drive screw after the firing member has been drivendistally from a home or starting position;

FIG. 27 is a partial cross-sectional perspective view of a portion ofthe surgical end effector, firing system and rotary drive system of thesurgical instrument of FIG. 1 according to at least one aspect of thepresent disclosure with an outer elastomeric joint assembly of anarticulation joint omitted for clarity;

FIG. 28 is another partial perspective view of a portion of the surgicalend effector, firing system and rotary drive system of FIG. 27 with anouter elastomeric joint assembly of an articulation joint and portionsof the elongate shaft assembly omitted for clarity;

FIG. 29 is a top view of the surgical end effector of FIG. 27articulated in a first direction relative to a portion of the elongateshaft assembly in accordance with at least one aspect of the presentdisclosure;

FIG. 30 is a side view of the surgical end effector of FIG. 29articulated in another direction relative to a portion of the elongateshaft assembly in accordance with at least one aspect of the presentdisclosure;

FIG. 31 is a perspective view of the surgical end effector of FIG. 29articulated in multiple planes with respect to a portion of the elongateshaft assembly in accordance with at least one aspect of the presentdisclosure;

FIG. 32 is a side elevational view of a portion of another surgicalinstrument that employs another outer elastomeric joint assembly inaccordance with at least one aspect of the present disclosure;

FIG. 33 is a partial cross-sectional perspective view of the surgicalinstrument of FIG. 32;

FIG. 34 is a perspective view of a portion of the outer elastomericjoint assembly of FIG. 32;

FIG. 35 is a cross-sectional end view of a portion of the surgicalinstrument of FIG. 19 taken along lines 35-35 in FIG. 19;

FIG. 36 is a cross-sectional end view of a portion of the surgicalinstrument of FIG. 19 taken along lines 36-36 in FIG. 19;

FIG. 37 is a partial cross-sectional view of a portion of an anvil capand an upper vertebra member of the surgical instrument of FIG. 19 inaccordance with at least one aspect of the present disclosure;

FIG. 38 is a side view of a portion of the surgical end effector of thesurgical instrument of FIG. 19 with an anvil thereof in an open positionin accordance with at least one aspect of the present disclosure andwith portions of the surgical end effector omitted for clarity;

FIG. 39 is a partial cross-sectional side view of the surgical endeffector of FIG. 38 with the anvil in an open position and the firingmember in the home or starting position in accordance with at least oneaspect of the present disclosure;

FIG. 40 is another partial cross-sectional side view of the surgical endeffector of FIG. 39 with the anvil in a partially closed position;

FIG. 41 is another partial cross-sectional side view of the surgical endeffector of FIG. 39 with the anvil in a fully closed position and thefiring member distally advancing through the surgical end effector;

FIG. 42 is a partial side elevational view of the surgical end effectorof FIG. 19 with portions thereof omitted for clarity to illustrate theanvil opening springs applying an opening motion to the anvil and withthe firing member in a home or starting position;

FIG. 43 is another partial side view of the surgical end effector ofFIG. 42, after the firing member has moved proximally a short distanceto apply a quick closure motion to the anvil for grasping purposes;

FIG. 44 is a cross-sectional view of the surgical end effector of FIG.19 with the jaws thereof in a closed position and the firing memberthereof in a proximal-most position;

FIG. 45 is another cross-sectional view of the surgical end effector ofFIG. 44, after the firing member has been distally advanced to theending position within the surgical end effector;

FIG. 46 is a perspective view of a portion of another surgicalinstrument;

FIG. 47 is a side elevational view of a surgical end effector of thesurgical instrument of FIG. 46, with the jaws thereof in an openposition;

FIG. 48 is another side view of the surgical end effector of FIG. 48with the jaws thereof in a closed position;

FIG. 49 is an exploded assembly view of a portion of the surgicalinstrument of FIG. 46;

FIG. 50 is a perspective view of a firing member and portions of anupper flexible spine assembly and a lower flexible spine assembly of afiring system of the surgical instrument of FIG. 46;

FIG. 51 is a cross-sectional side view of portions of the firing systemdepicted in FIG. 50;

FIG. 52 is a partial exploded assembly view of the upper flexible spineassembly and lower flexible spine assembly depicted in FIG. 51;

FIG. 53 is a partial cross-sectional end view of an upper portion of thefiring member depicted in FIG. 50;

FIG. 54 is a cross-sectional end view of the surgical end effector ofthe surgical instrument of FIG. 46, with the jaws thereof in a closedposition;

FIG. 55 is a view of a proximal face of an annular rib member of amovable exoskeleton assembly of the surgical instrument of FIG. 46;

FIG. 56 is a view of a distal face of the annular rib member of FIG. 55;

FIG. 57 is a side view of the annular rib member of FIGS. 55 and 56;

FIG. 58 is a partial cross-sectional view of a portion of the surgicalinstrument of FIG. 46;

FIG. 59 is a side view of an articulation joint of the surgicalinstrument of FIG. 46 when the surgical end effector thereof is in anunarticulated position;

FIG. 60 is another side view of the articulation joint of FIG. 59 whenthe surgical end effector is in an articulated position;

FIG. 61 is partial perspective view of a portion of the surgicalinstrument of FIG. 46 with the surgical end effector omitted forclarity;

FIG. 62 is another partial perspective view of a portion of the surgicalinstrument of FIG. 46;

FIG. 63 is another partial perspective view of a portion of the surgicalinstrument of FIG. 46;

FIG. 64 is a perspective view of a CV drive shaft assembly and a portionof the elongate shaft assembly of the surgical instrument of FIG. 46;

FIG. 65 is another perspective view of the CV drive shaft assembly andelongated shaft assembly of FIG. 64 with a drive cover embodimentinstalled around the CV drive shaft assembly;

FIG. 66 is another perspective view of the CV drive shaft assembly andelongated shaft assembly of FIG. 64 with another drive cover embodimentinstalled around the CV drive shaft assembly;

FIG. 67 is another perspective view of the CV drive shaft assembly andelongated shaft assembly of FIG. 64 with another drive cover embodimentinstalled around the CV drive shaft assembly;

FIG. 68 is a side view of a portion of the firing system of the surgicalinstrument of FIG. 46 with the drive cover of FIG. 67 installed aroundthe CV drive shaft assembly;

FIG. 69 is another side view of the portion of the firing system anddrive cover of FIG. 68;

FIG. 70 is a cross-sectional view of a portion of another surgicalinstrument;

FIG. 71 is a cross-sectional end view of a surgical end effector of thesurgical instrument of FIG. 70;

FIG. 72 is a cross-sectional side view of a rotary drive nut inengagement with drive components of the surgical instrument of FIG. 70;

FIG. 73 is a partial side view of a surgical end effector of anothersurgical instrument that employs a series of flexibly linked drivecomponents to drive a firing member through the surgical end effector;

FIG. 74 is a side view of a portion of the series of flexibly linkeddrive components of the surgical instrument of FIG. 73 prior toengagement with a rotary drive gear in the surgical end effector;

FIG. 75 is another side view of the portion of drive components of FIG.74 after being engaged with the rotary drive gear to form a rigid seriesof drive components;

FIG. 76 is a partial cross-sectional view of the rotary drive system ofthe surgical instrument of FIG. 74 with components in the series offlexible drive components in driving engagement with the rotary drivegear thereof;

FIG. 77 is a side view of a portion of rotary firing system and firingmember of another surgical instrument;

FIG. 78 is a side view of a portion of a rotary firing system and firingmember of another surgical instrument;

FIG. 79 is a side view of a portion of a rotary firing system and firingmember of another surgical instrument;

FIG. 80 is a partial view of another surgical instrument that employs arotary driven firing system to drive a firing member through a surgicalend effector with an anvil of the surgical end effector in an openposition;

FIG. 81 is another partial side view of the surgical instrument and endeffector of FIG. 80 with the anvil thereof in a closed position;

FIG. 82 is a perspective view of portions of the rotary driven firingsystem of the surgical instrument of FIG. 80;

FIG. 83 is a top view of a portion of the rotary driven firing systemdepicted in FIG. 82;

FIG. 84 is a perspective view of a guide member and rotary drive shaftof the rotary driven firing system of FIG. 83;

FIG. 85 is a perspective view of a portion of another flexible firingdrive assembly that may be employed with the firing drive system of FIG.83;

FIG. 86 is another perspective view of a portion of another flexiblefiring drive assembly embodiment that may be employed with the firingdrive system of FIG. 83;

FIG. 87 is a perspective view of a surgical end effector of anothersurgical instrument with an anvil thereof in an open position and thesurgical end effector in an unarticulated orientation;

FIG. 88 is an exploded assembly view of the surgical end effector andsurgical instrument of FIG. 87;

FIG. 89 is a side elevational view of an articulation joint of thesurgical instrument of FIG. 87;

FIG. 90 is a top view of the articulation joint of FIG. 89;

FIG. 91 is a perspective view of the articulation joint of FIG. 89 and acable-controlled closure pulley system for applying closing motions tothe anvil of the surgical end effector of FIG. 89;

FIG. 92 is a perspective view of a portion of the surgical end effectorof FIG. 89 articulated by the articulation joint of FIG. 89;

FIG. 93 is another perspective view of the cable-controlled closurepulley system of FIG. 91;

FIG. 94 is an end view of a pulley unit of the cable-controlled pulleysystem of FIG. 93;

FIG. 95 is a side elevational view of a first lateral alpha wrap pulleyof the pulley unit of FIG. 94;

FIG. 96 is a side cross-sectional view of a portion of the surgical endeffector of FIG. 89 with the anvil of the surgical end effector in anopen position;

FIG. 97 is another side elevational view of the surgical end effector ofFIG. 96 with the anvil in a closed position;

FIG. 98 is a perspective view of the articulation joint andcable-controlled closure system of the surgical instrument of FIG. 87with a central joint member and a distal joint member articulatedrelative to a proximal joint member of the articulation joint;

FIG. 99 is another perspective view of the articulation joint andcable-controlled closure system of the surgical instrument of FIG. 87with the distal joint member articulated through a second articulationplane relative to a central joint member of the articulation joint;

FIG. 100 is a side elevational view of portions of a firing drive systemof the surgical instrument of FIG. 87;

FIG. 101 is another perspective view of the firing drive system of FIG.100 with upper chain link features and lower chain link features inarticulated positions;

FIG. 102 is another side view of the firing drive system of FIG. 100with the upper chain link features and lower chain link features indriving engagement with a rotary drive screw of the firing drive system;

FIG. 103 is a cross-sectional end view of the surgical end effector ofFIG. 87 with the anvil thereof in a closed position;

FIG. 104 is a cross-sectional side view of a portion of the surgicalinstrument of FIG. 87 with the firing member in a starting position andthe anvil in a closed position;

FIG. 105 is an exploded assembly view of a rotary drive system of thesurgical instrument of FIG. 87;

FIG. 106 is a perspective view of a first drive shaft segment and asecond drive shaft segment of the rotary drive system of FIG. 105;

FIG. 107 is a perspective view of the surgical end effector of FIG. 87with the rotary drive system in an articulated orientation;

FIG. 108 is an exploded assembly view of an articulation joint and aportion of the rotary drive system of the surgical instrument of FIG.87;

FIG. 109 is a cross-sectional view of the articulation joint and rotarydrive system of FIG. 108 in an unarticulated orientation;

FIG. 110 is another cross-sectional view of the articulation joint androtary drive system of FIG. 109 with a proximal joint member of thearticulation joint articulated relative to a central joint member of thearticulation joint;

FIG. 111 is a partial side elevational view of the surgical instrumentof FIG. 87 illustrating one form of a cable tensioning system with thesurgical end effector in an unarticulated orientation;

FIG. 112 is another partial side view of the surgical instrument andcable tensioning system of FIG. 111 with the surgical end effector in anarticulated orientation;

FIG. 113 is a partial side elevational view of the surgical instrumentof FIG. 87 illustrating another form of a cable tensioning system withthe surgical end effector in an unarticulated orientation;

FIG. 114 is another partial side view of the surgical instrument andcable tensioning system of FIG. 113 with the surgical end effector in anarticulated orientation;

FIG. 115 is a perspective view of a portion of another surgicalinstrument embodiment;

FIG. 116 is a perspective view of a portion of the surgical instrumentof FIG. 115 with a surgical end effector portion thereof in anarticulated position relative to an elongate shaft portion thereof;

FIG. 117 is a side elevational view of the surgical end effector of FIG.116, with an anvil thereof in a closed position;

FIG. 118 is a top view of the surgical end effector of FIG. 117;

FIG. 119 is an exploded assembly perspective view of a portion of thesurgical instrument of FIG. 115;

FIG. 120 is a bottom cross sectional view of an articulation joint andportions of the anvil of the surgical instrument of FIG. 115;

FIG. 121 is an exploded assembly view of the articulation joint of FIG.120;

FIG. 122 is a side view of an annular disc member of the articulationjoint of FIG. 121;

FIG. 123 is a perspective view of the annular disc member of FIG. 122;

FIG. 124 is a view of a distal face of the annular disc member of FIG.122;

FIG. 125 is a view of a proximal face of the annular disc member of FIG.122;

FIG. 126 is a top view of a pulley unit of the surgical instrument ofFIG. 115;

FIG. 127 is a perspective view of a portion of the articulation jointand elongate shaft assembly of the surgical instrument of FIG. 115, withan outer shaft tube omitted for clarity;

FIG. 128 is a side elevational view of the pulley unit of FIG. 126;

FIG. 129 is another side elevational view of the pulley unit of FIG.126;

FIG. 130 is a perspective view of the pulley unit of FIG. 126 and acontinuum shaft of the articulation joint of the surgical instrument ofFIG. 115;

FIG. 131 is another perspective view of the pulley unit of FIG. 126 anda series of elastomeric annular spacer members of the articulation jointof the surgical instrument of FIG. 115;

FIG. 132 is another perspective view of the pulley unit, portions of afiring system and the articulation joint of the surgical instrument ofFIG. 115;

FIG. 133 is a perspective view of a portion of a firing system of thesurgical instrument of FIG. 115;

FIG. 134 is a partial cross-sectional view of the firing system of FIG.133;

FIG. 135 is a perspective view of the firing system, articulation joint,and a closure system of the surgical instrument of FIG. 115;

FIG. 136 is a partial cross sectional view of the surgical instrument ofFIG. 115 with the surgical end effector thereof in an unarticulatedposition;

FIG. 137 is a partial view of a differential drive assembly embodimentof the firing system of the surgical instrument of FIG. 115;

FIG. 138 is another partial cross sectional view of the surgicalinstrument of FIG. 115 with the surgical end effector thereof in anarticulated position;

FIG. 139 is another partial cross sectional view of the surgicalinstrument of FIG. 115 with the surgical end effector thereof in anarticulated position;

FIG. 140 is a perspective of a portion of another surgical instrumentembodiment;

FIG. 141 is a perspective view of an articulation joint of the surgicalinstrument of FIG. 140 in an unarticulated orientation;

FIG. 142 is another perspective view of the articulation joint of FIG.141 in another articulated orientation;

FIG. 143 is an exploded perspective view of the articulation joint ofFIG. 141;

FIG. 144 is a top view of the articulation joint of FIG. 141;

FIG. 145 is a cross-sectional view of the articulation joint of FIG. 144taken along line 145-145 in FIG. 144;

FIG. 146 is a side elevational view of the articulation joint of FIG.144;

FIG. 147 is another side elevation al view of the articulation joint ofFIG. 146 in an articulated orientation;

FIG. 148 is a perspective view of the articulation join of FIG. 141 inanother articulated orientation;

FIG. 149 is another perspective view of the articulation join of FIG.141 in another articulated orientation;

FIG. 150 is an end view of the proximal joint member of the articulationjoint of FIG. 141;

FIG. 151 is an end view of the distal joint member of the articulationjoint of FIG. 141;

FIG. 152 is a perspective view of a proximal cross pin assembly of thearticulation joint of FIG. 141;

FIG. 153 is a perspective view of another articulation joint embodiment;

FIG. 154 is a perspective view of an articulation joint portion ofanother surgical instrument embodiment;

FIG. 155 is another perspective view of the articulation jointarrangement of FIG. 154 with an outer shaft tube omitted for clarity;

FIG. 156 is an exploded perspective assembly view of the articulationjoint arrangement and firing drive system of the surgical instrument ofFIG. 154;

FIG. 157 is a perspective view of the articulation joint and firingsystem arrangement of FIG. 156 with an outer shaft tube omitted forclarity and wherein a firing member is in a starting position;

FIG. 158 is another perspective view of the articulation joint andfiring system of FIG. 157 after the firing member has been advanced to adistal position;

FIG. 159 is a partial cross-sectional view of a portion of the firingsystem of the surgical instrument of FIG. 154;

FIG. 160 is a partial view of a proximal differential drive assembly ofthe surgical instrument embodiment of FIG. 154;

FIG. 161 is a cross sectional end view through the proximal differentialdrive assembly of FIG. 160;

FIG. 162 is a side elevational view of the articulation joint and distaldifferential drive assembly of the surgical instrument of FIG. 154;

FIG. 163 is another side elevational view of the articulation joint anddistal differential drive assembly of FIG. 162 in an articulatedorientation;

FIG. 164 is a partial graphical depiction of reactive forces acting onpush coils of the surgical instrument of FIG. 154 when the articulationjoint thereof is in an articulated orientation and the firing member isbeing distally advanced;

FIG. 165 is another partial graphical depiction of reactive forcesacting on flexible outer tubes of the surgical instrument of FIG. 154when the articulation joint thereof is in an articulated orientation;

FIG. 166 is a perspective view of a central link member and flexiblejoint support assembly of the surgical instrument of FIG. 154;

FIG. 167 is a side elevational view of the articulation joint of thesurgical instrument of FIG. 154 in an unarticulated orientation;

FIG. 168 is a cross-sectional view of the articulation joint of FIG. 167taken along line 168-168 in FIG. 167; and

FIG. 169 is a partial perspective view of the articulation joint of thesurgical instrument of FIG. 154 in an articulated orientation with theflexible joint support assembly omitted for clarity.

DETAILED DESCRIPTION

Applicant of the present application owns the following U.S. patentapplications that were filed on even date herewith and which are eachherein incorporated by reference in their respective entireties:

-   -   U.S. patent application entitled SURGICAL INSTRUMENTS WITH        TORSION SPINE DRIVE ARRANGEMENTS, Attorney Docket No.        END9248USNP1/200084-1;    -   U.S. patent application entitled SURGICAL INSTRUMENTS WITH        FIRING MEMBER CLOSURE FEATURES, Attorney Docket No.        END9248USNP2/200084-2;    -   U.S. patent application entitled SURGICAL INSTRUMENTS WITH        SEGMENTED FLEXIBLE DRIVE ARRANGEMENTS, Attorney Docket No.        END9248USNP3/200084-3;    -   U.S. patent application entitled SURGICAL INSTRUMENTS WITH        FLEXIBLE BALL CHAIN DRIVE ARRANGEMENTS, Attorney Docket No.        END9248USNP4/200084-4;    -   U.S. patent application entitled SURGICAL INSTRUMENTS WITH        DOUBLE SPHERICAL ARTICULATION JOINTS WITH PIVOTABLE LINKS,        Attorney Docket No. END9248USNP5/200084-5;    -   U.S. patent application entitled SURGICAL INSTRUMENTS WITH        DOUBLE PIVOT ARTICULATION JOINT ARRANGEMENTS, Attorney Docket        No. END9248USNP6/200084-6;    -   U.S. patent application entitled SURGICAL INSTRUMENTS WITH        COMBINATION FUNCTION ARTICULATION JOINT ARRANGEMENTS, attorney        Docket No. END9248USNP7/200084-7;    -   U.S. patent application entitled METHOD OF OPERATING A SURGICAL        INSTRUMENT, Attorney Docket No. END9248USNP8/200084-8M;    -   U.S. patent application entitled SURGICAL INSTRUMENTS WITH        FLEXIBLE FIRING MEMBER ACTUATOR CONSTRAINT ARRANGEMENTS,        Attorney Docket No. END9248USNP10/200084-10;    -   U.S. patent application entitled ARTICULATABLE SURGICAL        INSTRUMENTS WITH ARTICULATION JOINTS COMPRISING FLEXIBLE        EXOSKELETON ARRANGEMENTS, Attorney Docket No.        END9248USNP11/200084-11; and    -   U.S. patent application entitled SURGICAL INSTRUMENTS WITH        DIFFERENTIAL ARTICULATION JOINT ARRANGEMENTS FOR ACCOMMODATING        FLEXIBLE ACTUATORS, Attorney Docket No. END9248USNP12/200084-12.

Numerous specific details are set forth to provide a thoroughunderstanding of the overall structure, function, manufacture, and useof the embodiments as described in the specification and illustrated inthe accompanying drawings. Well-known operations, components, andelements have not been described in detail so as not to obscure theembodiments described in the specification. The reader will understandthat the embodiments described and illustrated herein are non-limitingexamples, and thus it can be appreciated that the specific structuraland functional details disclosed herein may be representative andillustrative. Variations and changes thereto may be made withoutdeparting from the scope of the claims.

The terms “comprise” (and any form of comprise, such as “comprises” and“comprising”), “have” (and any form of have, such as “has” and“having”), “include” (and any form of include, such as “includes” and“including”) and “contain” (and any form of contain, such as “contains”and “containing”) are open-ended linking verbs. As a result, a surgicalsystem, device, or apparatus that “comprises,” “has,” “includes” or“contains” one or more elements possesses those one or more elements,but is not limited to possessing only those one or more elements.Likewise, an element of a system, device, or apparatus that “comprises,”“has,” “includes” or “contains” one or more features possesses those oneor more features, but is not limited to possessing only those one ormore features.

The terms “proximal” and “distal” are used herein with reference to aclinician manipulating the handle portion of the surgical instrument.The term “proximal” refers to the portion closest to the clinician andthe term “distal” refers to the portion located away from the clinician.It will be further appreciated that, for convenience and clarity,spatial terms such as “vertical”, “horizontal”, “up”, and “down” may beused herein with respect to the drawings. However, surgical instrumentsare used in many orientations and positions, and these terms are notintended to be limiting and/or absolute.

References to items in the singular should be understood to includeitems in the plural, and vice versa, unless explicitly stated otherwiseor clear from the text. Grammatical conjunctions are intended to expressany and all disjunctive and conjunctive combinations of conjoinedclauses, sentences, words, and the like, unless otherwise stated orclear from the context. Thus, the term “or” should generally beunderstood to mean “and/or”, etc.

Recitation of ranges of values herein are not intended to be limiting,referring instead individually to any and all values falling within therange, unless otherwise indicated herein, and each separate value withinsuch a range is incorporated into the disclosure as if it wereindividually recited herein. The words “about,” “approximately” or thelike, when accompanying a numerical value, are to be construed asindicating a deviation as would be appreciated by one of ordinary skillin the art to operate satisfactorily for an intended purpose. Similarly,words of approximation such as “approximately” or “substantially” whenused in reference to physical characteristics, should be construed tocontemplate a range of deviations that would be appreciated by one ofordinary skill in the art to operate satisfactorily for a correspondinguse, function, purpose or the like.

The use of any and all examples, or exemplary language (“e.g.,” “suchas,” or the like) provided herein, is intended merely to betterilluminate the embodiments and does not pose a limitation on the scopeof the embodiments. No language in the specification should be construedas indicating any unclaimed element as essential to the practice of theembodiments.

Various exemplary devices and methods are provided for performinglaparoscopic and minimally invasive surgical procedures. However, thereader will readily appreciate that the various methods and devicesdisclosed herein can be used in numerous surgical procedures andapplications including, for example, in connection with open surgicalprocedures. As the present Detailed Description proceeds, the readerwill further appreciate that the various instruments disclosed hereincan be inserted into a body in any way, such as through a naturalorifice, through an incision or puncture hole formed in tissue, etc. Theworking portions or end effector portions of the instruments can beinserted directly into a patient's body or can be inserted through anaccess device that has a working channel through which the end effectorand elongate shaft of a surgical instrument can be advanced.

It is common practice during various laparoscopic surgical procedures toinsert a surgical end effector portion of a surgical instrument througha trocar that has been installed in the abdominal wall of a patient toaccess a surgical site located inside the patient's abdomen. In itssimplest form, a trocar is a pen-shaped instrument with a sharptriangular point at one end that is typically used inside a hollow tube,known as a cannula or sleeve, to create an opening into the body throughwhich surgical end effectors may be introduced. Such arrangement formsan access port into the body cavity through which surgical end effectorsmay be inserted. The inner diameter of the trocar's cannula necessarilylimits the size of the end effector and drive-supporting shaft of thesurgical instrument that may be inserted through the trocar.

Regardless of the specific type of surgical procedure being performed,once the surgical end effector has been inserted into the patientthrough the trocar cannula, it is often necessary to move the surgicalend effector relative to the shaft assembly that is positioned withinthe trocar cannula in order to properly position the surgical endeffector relative to the tissue or organ to be treated. This movement orpositioning of the surgical end effector relative to the portion of theshaft that remains within the trocar cannula is often referred to as“articulation” of the surgical end effector. A variety of articulationjoints have been developed to attach a surgical end effector to anassociated shaft in order to facilitate such articulation of thesurgical end effector. As one might expect, in many surgical procedures,it is desirable to employ a surgical end effector that has as large arange of articulation as possible.

Due to the size constraints imposed by the size of the trocar cannula,the articulation joint components must be sized so as to be freelyinsertable through the trocar cannula. These size constraints also limitthe size and composition of various drive members and components thatoperably interface with the motors and/or other control systems that aresupported in a housing that may be handheld or comprise a portion of alarger automated system. In many instances, these drive members mustoperably pass through the articulation joint to be operably coupled toor operably interface with the surgical end effector. For example, onesuch drive member is commonly employed to apply articulation controlmotions to the surgical end effector. During use, the articulation drivemember may be unactuated to position the surgical end effector in anunarticulated position to facilitate insertion of the surgical endeffector through the trocar and then be actuated to articulate thesurgical end effector to a desired position once the surgical endeffector has entered the patient.

Thus, the aforementioned size constraints form many challenges todeveloping an articulation system that can effectuate a desired range ofarticulation, yet accommodate a variety of different drive systems thatare necessary to operate various features of the surgical end effector.Further, once the surgical end effector has been positioned in a desiredarticulated position, the articulation system and articulation jointmust be able to retain the surgical end effector in that locked positionduring the actuation of the end effector and completion of the surgicalprocedure. Such articulation joint arrangements must also be able towithstand external forces that are experienced by the end effectorduring use.

A variety of surgical end effectors exist that are configured to cut andstaple tissue. Such surgical end effectors commonly include a first jawfeature that supports a surgical staple cartridge and a second jaw thatcomprises an anvil. The jaws are supported relative to each other suchthat they can move between an open position and a closed position toposition and clamp target tissue therebetween. Many of these surgicalend effectors employ an axially moving firing member. In some endeffector designs, the firing member is configured to engage the firstand second jaws such that as the firing member is initially advanceddistally, the firing member moves the jaws to the closed position. Otherend effector designs employ a separate closure system that isindependent and distinct from the system that operates the firingmember.

The staple cartridge comprises a cartridge body. The cartridge bodyincludes a proximal end, a distal end, and a deck extending between theproximal end and the distal end. In use, the staple cartridge ispositioned on a first side of the tissue to be stapled and the anvil ispositioned on a second side of the tissue. The anvil is moved toward thestaple cartridge to compress and clamp the tissue against the deck.Thereafter, staples removably stored in the cartridge body can bedeployed into the tissue. The cartridge body includes staple cavitiesdefined therein wherein staples are removably stored in the staplecavities. The staple cavities are arranged in six longitudinal rows.Three rows of staple cavities are positioned on a first side of alongitudinal slot and three rows of staple cavities are positioned on asecond side of the longitudinal slot. Other arrangements of staplecavities and staples may be possible.

The staples are supported by staple drivers in the cartridge body. Thedrivers are movable between a first, or unfired position, and a second,or fired, position to eject the staples from the staple cavities. Thedrivers are retained in the cartridge body by a retainer which extendsaround the bottom of the cartridge body and includes resilient membersconfigured to grip the cartridge body and hold the retainer to thecartridge body. The drivers are movable between their unfired positionsand their fired positions by a sled. The sled is movable between aproximal position adjacent the proximal end and a distal positionadjacent the distal end. The sled comprises a plurality of rampedsurfaces configured to slide under the drivers and lift the drivers, andthe staples supported thereon, toward the anvil.

Further to the above, in these surgical end effectors, the sled is moveddistally by the firing member. The firing member is configured tocontact the sled and push the sled toward the distal end. Thelongitudinal slot defined in the cartridge body is configured to receivethe firing member. The anvil also includes a slot configured to receivethe firing member. The firing member further comprises a first cam whichengages the first jaw and a second cam which engages the second jaw. Asthe firing member is advanced distally, the first cam and the second camcan control the distance, or tissue gap, between the deck of the staplecartridge and the anvil. The firing member also comprises a knifeconfigured to incise the tissue captured intermediate the staplecartridge and the anvil. It is desirable for the knife to be positionedat least partially proximal to the ramped surfaces such that the staplesare ejected ahead of the knife.

Many surgical end effectors employ an axially movable firing beam thatis attached to the firing member and is used to apply axial firing andretraction motions to the firing member. Many of such firing beamscomprise a laminated construction that affords the firing beam with somedegree of flexure about the articulation joint. As the firing beamtraverses the articulation joint, the firing beam can applyde-articulation forces to the joint and can cause the beam to buckle. Toprevent the firing beam from buckling under pressure, the articulationjoint is commonly provided with lateral supports or “blow-out” platefeatures to support the portion of the beam that traverses thearticulation joint. To advance the firing beam through an angle ofgreater than sixty degrees, for example, a lot of axial force isrequired. This axial force must be applied to the firing member in abalanced manner to avoid the firing member from binding with the jaws asthe firing member moves distally. Any binding of the firing member withthe jaws can lead to component damage and wear as well as require anincreased amount of axial drive force to drive the firing member throughthe clamped tissue.

Other end effector designs employ a firing member that is rotarypowered. In many of such designs, a rotary drive shaft extends throughthe articulation joint and interfaces with a rotatable firing memberdrive shaft that is rotatably supported within one of the jaws. Thefiring member threadably engages the rotatable firing member drive shaftand, as the rotatable firing member drive shaft is rotated, the firingmember is driven through the end effector. Such arrangements require thesupporting jaw to be larger to accommodate the firing member driveshaft. In such devices, a lower end of the firing member commonlyoperably interfaces with the drive shaft which can also result in anapplication of forces that tend to unbalance the firing member as it isdriven distally.

FIGS. 1-4 illustrate one form of a surgical instrument 10 that mayaddress many of the challenges facing surgical instruments witharticulatable end effectors that are configured to cut and fastentissue. In various embodiments, the surgical instrument 10 may comprisea handheld device. In other embodiments, the surgical instrument 10 maycomprises an automated system sometimes referred to as arobotically-controlled system, for example. In various forms, thesurgical instrument 10 comprises a surgical end effector 1000 that isoperably coupled to an elongate shaft assembly 2000. The elongate shaftassembly 2000 may be operably attached to a housing 2002. In oneembodiment, the housing 2002 may comprise a handle that is configured tobe grasped, manipulated, and actuated by the clinician. In otherembodiments, the housing 2002 may comprise a portion of a robotic systemthat houses or otherwise operably supports at least one drive systemthat is configured to generate and apply at least one control motionwhich could be used to actuate the surgical end effectors disclosedherein and their respective equivalents. In addition, various componentsmay be “housed” or contained in the housing or various components may be“associated with” a housing. In such instances, the components may notbe contained with the housing or supported directly by the housing. Forexample, the surgical instruments disclosed herein may be employed withvarious robotic systems, instruments, components and methods disclosedin U.S. Pat. No. 9,072,535, entitled SURGICAL STAPLING INSTRUMENTS WITHROTATABLE STAPLE DEPLOYMENT ARRANGEMENTS, which is incorporated byreference herein in its entirety.

In one form, the surgical end effector 1000 comprises a first jaw 1100and a second jaw 1200. In the illustrated arrangement, the first jaw1100 comprises an elongate channel 1110 that comprises a proximal end1112 and a distal end 1114 and is configured to operably support asurgical staple cartridge 1300 therein. The surgical staple cartridge1300 comprises a cartridge body 1302 that has an elongate slot 1304therein. A plurality of surgical staples or fasteners (not shown) arestored therein on drivers (not shown) that are arranged in rows on eachside of the elongate slot 1304. The drivers are each associated withcorresponding staple cavities 1308 that open through a cartridge decksurface 1306. The surgical staple cartridge 1300 may be replaced afterthe staples/fasteners have been discharged therefrom. Other embodimentsare contemplated wherein the elongate channel 1110 and/or the entiresurgical end effector 1000 may is discarded after the surgical staplecartridge 1300 has been used. Such end effector arrangements may bereferred to as “disposable loading units”, for example.

In the illustrated arrangement, the second jaw 1200 comprises an anvil1210 that comprises an elongate anvil body 1212 that comprises aproximal end 1214 and a distal end 1216. In one arrangement, a pair ofstiffening rods or members 1213 may be supported in the anvil body 1212to provide the anvil body 1212 with added stiffness and rigidity. Theanvil body 1212 comprises a staple-forming undersurface 1218 that facesthe first jaw 1100 and may include a series of staple-forming pockets(not shown) that corresponds to each of the staples or fasteners in thesurgical staple cartridge 1300. The anvil body 1212 may further includea pair of downwardly extending tissue stop features 1220 that are formedadjacent the proximal end 1214 of the anvil body 1212. One tissue stopfeature 1220 extends from each side of the anvil body 1212 such that adistal end 1222 on each tissue stop corresponds to the proximal-moststaples/fasteners in the surgical staple cartridge 1300. When the anvil1210 is moved to a closed position onto tissue positioned between thestaple-forming undersurface 1218 of the anvil 1210 and the cartridgedeck surface 1306 of the surgical staple cartridge 1300, the tissuecontacts the distal ends 1222 of the tissue stop features 1220 toprevent the tissue from migrating proximally past the proximal-moststaples/fasteners to thereby ensure that the tissue that is cut is alsostapled. When the surgical staple cartridge is “fired” as will bediscussed in further detail below, the staples/fasteners supportedwithin each staple cavity are driven out of the staple cavity 1308through the clamped tissue and into forming contact with thestaple-forming undersurface 1218 of the anvil 1210.

As can be seen in FIGS. 5 and 6, the proximal end 1214 of the anvil body1212 comprises an anvil mounting portion 1230 that includes a pair oflaterally extending mounting pins 1232 that are configured to bereceived in corresponding mounting cradles or pivot cradles 1120 formedin the proximal end 1112 of the elongate channel 1110. The mounting pins1232 are pivotally retained within the mounting cradles 1120 by an anvilcap 1260 that may be attached to the proximal end 1112 of the elongatechannel 1110 by mechanical snap features 1261 that are configured toengage retention formations 1113 on the elongate channel 1110. See FIG.5. In other arrangements, the anvil cap 1260 may be attached to theelongate channel 1110 by welding, adhesive, etc. Such arrangementfacilitates pivotal travel of the anvil 1210 relative to the surgicalstaple cartridge 1300 mounted in the elongate channel 1110 about a pivotaxis PA between an open position (FIG. 1) and a closed position (FIGS.2-5). Such pivot axis PA may be referred to herein as being “fixed” inthat the pivot axis does not translate or otherwise move as the anvil1200 is pivoted from an open position to a closed position.

In the illustrated arrangement, the elongate shaft assembly 2000 definesa shaft axis SA and comprises a proximal shaft portion 2100 that mayoperably interface with a housing of the control portion (e.g., handheldunit, robotic tool driver, etc.) of the surgical instrument 10. Theelongate shaft assembly 2000 further comprises an articulation joint2200 that is attached to the proximal shaft portion 2100 and thesurgical end effector 1000. In various instances, the proximal shaftportion 2100 comprises a hollow outer tube 2110 that may be operablycoupled to a housing 2002. See FIG. 2. As can be seen in FIG. 6, theproximal shaft portion 2100 may further comprise a rigid proximalsupport shaft 2120 that is supported within the hollow outer tube 2110and extends from the housing to the articulation joint 2200. Theproximal support shaft 2120 may comprise a first half 2120A and a secondhalf 2120B that may be coupled together by, for example, welding,adhesive, etc. The proximal support member 2120 comprises a proximal end2122 and a distal end 2124 and includes an axial passage 2126 thatextends therethrough from the proximal end 2122 to the distal end 2124.

As was discussed above, many surgical end effectors employ a firingmember that is pushed distally through a surgical staple cartridge by anaxially movable firing beam. The firing beam is commonly attached to thefiring member in the center region of the firing member body. Thisattachment location can introduce an unbalance to the firing member asit is advanced through the end effector. Such unbalance can lead toundesirable friction between the firing member and the end effectorjaws. The creation of this additional friction may require anapplication of a higher firing force to overcome such friction as wellas can cause undesirable wear to portions of the jaws and/or the firingmember. An application of higher firing forces to the firing beam mayresult in unwanted flexure in the firing beam as it traverses thearticulation joint. Such additional flexure may cause the articulationjoint to de-articulate—particularly when the surgical end effector isarticulated at relatively high articulation angles. The surgicalinstrument 10 employs a firing system 2300 that may address many if notall of these issues as well as others.

As can be seen in FIGS. 5-11, in at least one embodiment, the firingsystem 2300 comprises a firing member 2310 that includes avertically-extending firing member body 2312 that comprises a top firingmember feature 2320 and a bottom firing member feature 2350. A tissuecutting blade 2314 is attached to or formed in the vertically-extendingfiring member body 2312. See FIGS. 9 and 11. In at least onearrangement, it is desirable for the firing member 2310 to pass throughthe anvil body 1212 with low friction, high strength and high stiffness.In the illustrated arrangement, the top firing member feature 2320comprises a top tubular body 2322 that has a top axial passage 2324extending therethrough. See FIG. 10. The bottom firing member feature2350 comprises a bottom tubular body 2352 that has a bottom axialpassage 2354 extending therethrough. In at least one arrangement, thetop firing member feature 2320 and the bottom firing member feature 2350are integrally formed with the vertically-extending firing member body2312. As can be seen in FIG. 12, the anvil body 1212 comprises anaxially extending anvil slot 1240 that has a cross-sectional shape thatresembles a “keyhole”. Similarly, the elongate channel 1110 comprises anaxially extending channel slot 1140 that also has a keyholecross-sectional shape.

Traditional firing member arrangements employ long flexible cantileverwings that extend from a top portion and a bottom portion of the firingmember. These cantilever wings slidably pass through slots in the anviland channel that are commonly cut with a rectangular t-cutter whichtended to produce higher friction surfaces. Such long cantilever wingshave minimum surface area contact with the anvil and channel and canresult in galling of those components. The keyhole-shaped channel slot1140 and keyhole-shaped anvil slot 1240 may be cut with a round t-cutterand may be finished with a reamer/borer which will result in thecreation of a lower friction surface. In addition, the top tubular body2322 and the bottom tubular body 2352 tend to be stiffer than the priorcantilever wing arrangements and have increased surface area contactwith the anvil and channel, respectively which can reduce galling andlead to a stronger sliding connection. Stated another way, because theanvil slot 1240 and the channel slot 1140 are keyhole-shaped and haveless material removed than a traditional rectangular slot, the geometryand increased material may result in a stiffer anvil and channel whencompared to prior arrangements.

Turning to FIGS. 9-11, in one arrangement, the firing system 2300further comprises an upper flexible spine assembly 2400 that is operablycoupled to the top firing member feature 2320 and a lower flexible spineassembly 2500 that is operably coupled to the bottom firing memberfeature 2350. In at least one embodiment, the upper flexible spineassembly 2400 comprises an upper series 2410 of upper vertebra members2420 that are loosely coupled together by an upper flexible couplermember 2402 that is attached to the top firing member feature 2320. Theupper flexible coupler member 2402 may comprises a top cable 2404 thatextends through the top axial passage 2324 in the top firing memberfeature 2320 and a distal end 2406 of the top cable 2404 is attached toa retainer ferrule 2408 that is secured with the top axial passage 2324.

As can be seen in FIG. 13, each upper vertebra member 2420 comprises anupper vertebra body portion 2422 that has a proximal end 2424 and adistal end 2428. An upper hollow passage 2429 extends through the uppervertebra body portion 2422 to accommodate passage of the upper flexiblecoupler member 2402 therethrough. Each upper vertebra member 2420further comprises a downwardly extending upper drive feature or uppervertebra member tooth 2450 that protrudes from the upper vertebra bodyportion 2422. Each upper vertebra member tooth 2450 has a helix-shapedproximal upper face portion 2452 and a helix-shaped distal upper faceportion 2454. Each proximal end 2424 of the upper vertebra body portions2422 has an upper proximal mating feature 2426 therein and each distalend 2428 has an upper distal mating feature 2430 formed therein. In atleast one embodiment, the upper proximal mating feature 2426 comprises aconcave recess 2427 and each upper distal mating feature 2430 comprisesa convex mound 2431. When arranged in the upper series 2410, the convexmound 2431 on one upper vertebra member 2420 contacts and mates with theconcave recess 2427 on an adjacent upper vertebra member 2420 in theupper series 2410 to maintain the upper vertebra members 2420 roughly inalignment so that the helix-shaped proximal upper face portion 2452 anda helix-shaped distal upper face portion 2454 on each respective uppertooth 2450 can be drivingly engaged by a rotary drive screw 2700 as willbe discussed in further detail below.

Similarly, in at least one embodiment, the lower flexible spine assembly2500 comprises a lower series 2510 of lower vertebra members 2520 thatare loosely coupled together by a lower flexible coupler member 2502that is attached to the bottom firing member feature 2350. The lowerflexible coupler member 2502 may comprises a lower cable 2504 thatextends through the bottom axial passage 2354 in the bottom firingmember feature 2350 and a distal end 2506 of the bottom cable 2504 isattached to a retainer ferrule 2508 that is secured with the bottomaxial passage 2354.

As can be seen in FIG. 14, each lower vertebra member 2520 comprises alower vertebra body portion 2522 that has a proximal end 2524 and adistal end 2528. A lower hollow passage 2529 extends through the lowervertebra body portion 2522 to accommodate passage of the lower flexiblecoupler member 2502 therethrough. Each lower vertebra member 2520further comprises an upwardly extending lower drive feature or lowervertebra member tooth 2550 that protrudes upward from the lower vertebrabody portion 2522. Each lower vertebra member tooth 2550 has ahelix-shaped proximal lower face portion 2552 and a helix-shaped distallower face portion 2554. Each proximal end 2524 of the lower vertebrabody portions 2522 has a lower proximal mating feature 2526 therein andeach distal end 2528 has a lower distal mating feature 2530 formedtherein. In at least one embodiment, the lower proximal mating feature2526 comprises a concave recess 2527 and each lower distal matingfeature 2530 comprises a convex mound 2531. When arranged in the lowerseries 2510, the convex mound 2531 on one lower vertebra member 2520contacts and mates with the concave recess 2527 on an adjacent lowervertebra member 2520 in the lower series 2510 to maintain the lowervertebra members 2520 roughly in alignment so that the helix-shapedproximal lower face portion 2552 and a helix-shaped distal lower faceportion 2554 on each respective lower vertebra member tooth 2550 can bedrivingly engaged by a rotary drive screw 2700 as will be discussed infurther detail below.

Now turning to FIGS. 5, 7, and 8, in at least one arrangement, thefiring drive system 2300 further comprises a rotary drive screw 2700that is configured to drivingly interface with the upper series 2410 ofupper vertebra members 2420 and the lower series 2510 of lower vertebramembers 2520. In the illustrated arrangement, the rotary drive screw2700 is driven by a rotary drive system 2600 that comprises a proximalrotary drive shaft 2610 that is rotatably supported within the axialpassage 2126 within the proximal support shaft 2120. See FIG. 7. Theproximal rotary drive shaft 2610 comprises a proximal end 2612 and adistal end 2614. The proximal end 2612 may interface with a gear box2004 or other arrangement that is driven by a motor 2006 or other sourceof rotary motion housed in the housing of the surgical instrument. SeeFIG. 2. Such source of rotary motion causes the proximal rotary driveshaft to rotate about the shaft axis SA within the axial passage 2126 inthe proximal support shaft 2120.

The proximal rotary drive shaft 2610 is operably supported within theelongate shaft assembly 2000 in a location that is proximal to thearticulation joint 2200 and operably interfaces with a constant velocity(CV) drive shaft assembly 2620 that “spans” or extends axially throughthe articulation joint 2200. As can be seen in FIGS. 8, 16, and 17, inat least one arrangement, the CV drive shaft assembly 2620 comprises aproximal CV drive assembly 2630 and a distal CV drive shaft 2670. Theproximal CV drive assembly 2630 comprises a proximal shaft segment 2632that consists of an attachment shaft 2634 that is configured to benon-rotatably received within a similarly-shaped coupler cavity 2616 inthe distal end 2614 of the proximal rotary drive shaft 2610. Theproximal shaft segment 2632 operably interfaces with a series 2640 ofmovably coupled drive joints 2650.

As can be seen in FIG. 18, in at least one arrangement, each drive joint2650 comprises a first or distal sphere portion 2660 and a second orproximal sphere portion 2652. The distal sphere portion 2660 is largerthan the proximal sphere portion 2652. The distal sphere portion 2660comprises a socket cavity 2662 that is configured to rotatably receive aproximal sphere portion 2652 of an adjacent drive joint 2650 therein.Each proximal sphere portion 2652 comprises a pair of diametricallyopposed joint pins 2654 that are configured to be movably received incorresponding pin slots 2664 in the distal sphere portion 2660 of anadjacent drive joint 2650 as can be seen in FIG. 16. A proximal sphereportion 2652P of a proximal-most drive joint 2650P is rotatably receivedin a distal socket portion 2636 of the proximal shaft segment 2632 asshown in FIG. 16. The joint pins 2654P are received within correspondingpin slots 2637 in the distal socket portion 2636. As can be further seenin FIG. 16, a distal-most drive joint 2650D in the series 2640 ofmovably coupled drive joints 2650 is movably coupled to a distal CVdrive shaft 2670.

In at least one arrangement, the distal CV drive shaft 2670 comprises aproximal sphere portion 2672 that is sized to be movably received in thesocket cavity 2662D in the distal-most drive joint 2650D. The proximalsphere portion 2672 includes joint pins 2674 that are movably receivedin the pin slots 2664D in the distal-most drive joint 2650D. The distalCV drive shaft 2670 further comprises a distally extending shaft stem2676 that is configured to be non-rotatably coupled to the rotary drivescrew 2700 that is positioned distal to the articulation joint 2200. Thedistal CV drive shaft 2670 includes a flange 2677 and a mounting barrelportion 2678 for receiving a thrust bearing housing 2680 thereon.

In the illustrated arrangement, when the series 2640 of movably coupleddrive joints 2650 articulates, the joint pins 2674 remain in thecorresponding pin slots 2664 of an adjacent drive joint 2650. In theexample illustrated in FIG. 18, each drive joint may be capable ofapproximately eighteen degrees of articulation in the pitch and yawdirections. FIG. 16 illustrates an angle of the series of 2640 of drivejoints 2650 when each drive joint 2650 in the series are fullyarticulated ninety degrees in pitch and yaw which yields an angle α ofapproximately 100.9 degrees. In such arrangement, the outer surface ofeach distal sphere portion 2660 clears the outer surface of the adjacentor adjoining proximal sphere portion 2652 allowing for unrestrictedmotion until the eighteen degree limit is reached. The rigid design andlimited small angles allow the series 2640 of movably coupled drivejoints 2650 to carry high loads torsionally at an overall large angle.

In the illustrated arrangement, the articulation joint 2200 comprises anarticulation joint spring 2230 that is supported within an outerelastomeric joint assembly 2210. The outer elastomeric joint assembly2210 comprises a distal end 2212 that is attached to the proximal end1112 of the elongate channel 1110. For example, as can be seen in FIG.6, the distal end 2212 of the outer elastomeric joint assembly 2210 isattached to the proximal end 1112 of the elongate channel 1110 by a pairof cap screws 2722 that extend through a distal mounting bushing 2720 tobe threadably received in the proximal end 1112 of the elongate channel1110. A proximal end 2214 of the elastomeric joint assembly 2210 isattached to the distal end 2124 of the proximal support shaft 2120. Theproximal end 2214 of the elastomeric joint assembly 2210 is attached tothe distal end 2124 of the proximal support member 2120 by a pair of capscrews 2732 that extend through a proximal mounting bushing 2750 to bethreadably received in threaded inserts 2125 mounted within the distalend 2124 of the proximal support shaft 2120.

To prevent the drive joints 2650 from buckling during articulation, theseries 2640 of movably coupled drive joints 2650 extend through at leastone low friction articulation joint spring 2730 that is supported withinthe outer elastomeric joint assembly 2210. See FIG. 19. The articulationjoint spring 2730 is sized relative to the drive joints 2650 such that aslight radial clearance is provided between the articulation jointspring 2730 and the drive joints 2650. The articulation joint spring2730 is designed to carry articulation loads axially which may besignificantly lower than the torsional firing loads. The joint spring(s)is longer than the series 2640 of drive joints 2650 such that the drivejoints are axially loose. If the “hard stack” of the series 2640 ofdrive joints 2650 is longer than the articulation joint spring(s) 2730hard stack, then the drive joints 2650 may serve as an articulationcompression limiter causing firing loads and articulation loads toresolve axially through the series 2640 of the drive joints 2650. Whenthe firing loads resolve axially through the series 2640 of the drivejoints 2650, the loads may try to straighten the articulation joint 2200or in other words cause de-articulation. If the hard stack of thearticulation joint spring(s) 2730 is longer than the hard stack of theseries 2640 of the drive joints 2650, the firing loads will then becontained within the end effector and no firing loads will resolvethrough the drive joints 2650 or through the springs(s) 2730.

To further ensure that the drive joints 2650 are always engaged witheach other, a proximal drive spring 2740 is employed to apply an axialbiasing force to the series 2640 of drive joints 2650. For example, ascan be seen in FIGS. 8, 19, and 20, the proximal drive spring 2740 ispositioned between the proximal mounting bushing 2734 and a supportflange that is formed between the distal socket portion 2636 and aproximal barrel portion 2638 of the proximal shaft segment 2632. In onearrangement, the proximal drive spring 2740 may comprise an elastomericO-ring/bushing received on the proximal barrel portion 2638 of theproximal shaft segment 2632. The proximal drive spring 2740 lightlybiases the drive joints 2650 together to decrease any gaps that mayoccur during articulation. This ensures that the drive joints 2650transfer loads torsionally. It will be appreciated, however, that in atleast one arrangement, the proximal drive spring 2740 does not apply ahigh enough axial load to cause firing loads to translate through thearticulation joint 2200.

As can be seen in FIGS. 9 and 10, the top firing member feature 2320 onthe firing member 2310 comprises a distal upper firing member toothsegment 2330 that is equivalent to one half of an upper tooth 2450 oneach upper vertebra member 2420. In addition, a proximal upper firingmember tooth 2336 that is identical to an upper tooth 2450 on each uppervertebra member 2420 is spaced from the distal upper firing member toothsegment 2330. The distal upper firing member tooth segment 2330 and theproximal upper firing member tooth 2336 may be integrally formed withthe top firing member feature 2320 of the firing member 2310. Likewise,the bottom firing member feature 2350 of the firing member 2310comprises a distal lower firing member tooth 2360 and a proximal lowerfiring member tooth 2366 that are integrally formed on the bottom firingmember feature 2350. For example, in at least one arrangement, thefiring member 2310 with the rigidly attached teeth 2330, 2336, 2360, and2366 may be fabricated at one time as one unitary component usingconventional metal injection molding techniques.

As indicated above, each of the upper vertebra members 2520 is movablyreceived on an upper flexible coupler member 2402 in the form of a topcable 2404. As was described above, the distal end 2406 of the top cable2404 is secured to the top firing member feature 2320 of the firingmember 2310. Similarly, each of the lower vertebra members 2520 ismovably received on a lower flexible coupler member 2502 in the form ofa lower cable 2504. A distal end 2506 of the lower cable 2504 is securedto the bottom firing member feature 2350 of the firing member 2310. Inat least one arrangement, the top cable 2404 and the bottom cable 2504extend through the proximal shaft portion 2100 and, as will be discussedin further detail below, may interface with a bailout arrangementsupported in the housing for retracting the firing member 2310 back toits home or starting position should the firing member drive systemfail.

Turning again to FIG. 8, the axial length AL_(u) of the upper series2410 of upper vertebra members 2420 and the axial length AL_(l) of thelower series 2510 of lower vertebra members 2520 are equal and must besufficiently long enough to facilitate the complete distal advancementof the firing member 2310 from the home or starting position to adistal-most ending position within the staple cartridge while theproximal-most upper vertebra members 2420 in the upper series 2410 ofupper vertebra members 2420 and the proximal-most lower vertebra members2520 in the lower series 2510 of lower vertebra members 2520 remain indriving engagement with the rotary drive screw 2700. As can be seen inFIG. 8, an upper compression limiting spring 2421 is configured tointerface with a proximal-most upper vertebra member 2420P in the upperseries 2410 of upper vertebra members 2420. The upper compressionlimiting spring 2421 is journaled on the top cable 2404 and is retainedin biasing engagement with the proximal-most upper vertebra member 2420Pby an upper spring holder 2423 that is retained in position by an upperferrule 2425 that is crimped onto the top cable 2404. The top cable 2404extends through an upper hypotube 2433 that is supported in the proximalsupport shaft. Likewise, a lower compression limiting spring 2521 isconfigured to interface with a proximal-most, lower vertebra member2520P in the lower series 2510 of lower vertebra members 2520. The lowercompression spring 2521 is journaled on the lower cable 2504 and isretained in biasing engagement with the proximal-most, lower vertebramember 2520P by a lower spring holder 2523 that is retained in positionby a lower ferrule 2525 that is crimped onto the lower cable 2504. Thelower cable 2504 extends through a lower hypotube 2533 that is supportedin the proximal support shaft.

When the upper vertebra members 2420 and the lower vertebra members 2520angle through the articulation joint (after the end effector has beenpositioned in an articulated position), the gaps between the respectivevertebra members 2420, 2520 increase in each series 2410, 2510 whichcauses the springs 2421, 2521 to become tighter. The compressionlimiting springs 2421, 2521 provide enough slack in the cables 2404,2504, respectively to enable the vertebra members 2420, 2520 anglethrough the most extreme articulation angles. If the cables 2404, 2504are pulled too tight, the spring holders 2423, 2523 will contact theirrespective proximal-most vertebra members 2420P, 2520P. Such compressionlimiting arrangements ensure that the vertebra members 2420, 2520 intheir respective series 2410, 2510 always remain close enough togetherso that the rotary drive screw 2700 will always drivingly engage them inthe manner discussed in further detail below. When the vertebra members2420, 2520 are aligned straight again, the compression limiting springs2421, 2521 may partially relax while still maintaining some compressionbetween the vertebra members.

As indicated above, when the upper vertebra members 2420 are arranged inthe upper series 2410 and lower vertebra members 2520 are arranged inthe lower series 2510, the convex mounds and concave recesses in eachvertebra member as well as the compression limiter springs serve tomaintain the upper and lower vertebra members in relatively linearalignment for driving engagement by the rotary drive screw 2700. As canbe seen in FIGS. 9 and 10, when the upper vertebra members 2420 are inlinear alignment, the upper teeth 2450 are spaced from each other by anopening space generally designated as 2460 that facilitates drivingengagement with the helical drive thread 2170 on the rotary drive screw.Similarly, when the lower vertebra members 2520 are in linear alignment,the lower vertebra member teeth 2550 are spaced from each other by anopening space generally designated as 2560 that facilitates drivingengagement with the helical drive thread 2170 of the rotary drive screw2700.

Turning to FIGS. 8 and 22, the rotary drive screw 2700 comprises a screwbody 2702 that has a socket 2704 therein for receiving the distallyextending shaft stem 2676 of the distal CV drive shaft 2670. An internalradial groove 2714 (FIG. 10) is formed in the screw body 2702 forsupporting a plurality of ball bearings 2716 therein. In onearrangement, for example, 12 ball bearings 2716 are employed. The radialgroove 2714 supports the ball bearings 2716 between the screw body 2702and a distal end of the thrust bearing housing 2680. The ball bearings2716 serve to distribute the axial load of the rotary drive screw 2700and significantly reduce friction through the balls' rolling motion.

As can be seen in FIG. 23, a helical drive thread 2710 is providedaround the screw body 2702 and serves to form a proximal thread scoopfeature 2712. The proximal thread scoop feature 2712 is formed with afirst pitch 2713 and the remaining portion of the helical drive thread2710 is formed with a second pitch 2715 that differs from the firstpitch 2713. In FIGS. 22 and 23, area 2718 illustrates where the firstpitch 2713 and the second pitch 2715 converge. In at least oneembodiment, the first pitch 2713 is larger than the second pitch 2715 toensure that the rotary drive screw 2700 captures and “scoops up” ordrivingly engages every upper vertebra member 2420 and every lowervertebra member 2520. As can be seen in FIG. 24, a proximal end 2717 ofthe helical drive thread 2710 that has the first pitch 2713 has scoopedinto the into the opening space 2560 between two adjacent lower vertebramember teeth 2550A and 2550B while the center portion 2719 of thehelical drive thread 2710 that has the second pitch 2715 is in drivingengagement with the helix-shaped distal lower face portion 2554 on thelower vertebra member tooth 2550B and the helix-shaped proximal lowerface portion 2552 on the proximal lower firing member tooth 2366. As canalso be appreciated, the scoop feature 2712 may not contact thehelix-shaped distal lower face portion 2554A of the lower vertebramember tooth 2550A as it scoops up the lower vertebra member tooth 2550Bwhen driving the firing member 2310 distally. The helical drive thread2710 interacts with the teeth 2450 of the upper vertebra members 2420 ina similar manner.

A power screw is a threaded rod with a full three hundred sixty degreenut around it. Rotation of the power screw causes the nut to advance ormove longitudinally. In the present arrangements, however, due to spaceconstraints, a full three hundred sixty degree nut cannot fit inside theend effector. In a general sense, the upper flexible spine assembly 2400and the lower flexible spine assembly 2500 comprise aradially/longitudinally segmented “power screw nut” that is rotatablydriven by the rotary drive screw 2700. When the rotary drive screw isrotated in a first rotary direction, the rotary drive screw 2700 drivesone or more vertebra members in each of the upper series and lowerseries of vertebra members longitudinally while the vertebra members2420, 2520 stay in the same locations radially. The upper series 2410and lower series 2510 are constrained from rotating around the rotarydrive screw 2700 and can only move longitudinally. In one arrangement,the upper vertebra members 2420 in the upper series 2410 and the lowervertebra members 2520 in the lower series 2510 only surround the rotarydrive screw 2700 with less than ten degrees each.

FIG. 25 illustrates the firing member 2310 in the home or startingposition. As can be seen in FIG. 25, a portion of the helical drivethread 2710 on the rotary drive screw 2700 is engaged between the distalupper firing member tooth segment 2330 and the proximal upper firingmember tooth 2336 and another portion of the helical drive thread 2710is engaged between the distal lower firing member tooth 2360 and aproximal lower firing member tooth 2366 on the firing member 2310. Sucharrangement enables the rotary drive screw 2700 to precisely control thedistal and proximal movement of the firing member 2310 which, as will bediscussed in further detail below, can result in the precise movement ofthe anvil 1210. Once the firing member 2310 has been sufficientlydistally advanced during a firing stroke, the helical drive thread 2710operably engages the teeth on the upper and lower vertebras. See FIG.26.

The surgical instrument 10 also comprises an articulation system 2240that is configured to apply articulation motions to the surgical endeffector 1000 to articulate the surgical end effector relative to theelongate shaft assembly 2000. In at least one arrangement, for example,the articulation system comprises four articulation cables 2242, 2246,2250, and 2254 that extend through the elongate shaft assembly 2000. SeeFIG. 27. In the illustrated arrangement, the articulation cables 2242,2246 pass through the proximal mounting bushing 2750, the proximal end2214 of the elastomeric joint assembly 2210, as well as a central ribsegment 2216 to be secured to the distal end 2212 of the elastomericjoint assembly 2210 or other portion of the surgical instrument.Likewise, the articulation cables 2250 and 2254 extend through theproximal mounting bushing 2750, the proximal end 2214 of the elastomericjoint assembly 2210, as well as a central rib segment 2218 to be securedto the distal end 2212 of the elastomeric joint assembly 2210 or otherportion of the surgical end effector. The cables 2242, 2246, 2250, and2254 operably interface with an articulation control system that issupported in the housing of the surgical instrument 10. For example, aproximal portion of each cable 2242, 2246, 2250, and 2254 may be spooledon a corresponding rotary spool or cable-management system 2007 (FIG. 2)in the housing portion of the surgical instrument 10 that is configuredto payout and retract each cable 2242, 2246, 2250, and 2254 in desiredmanners. The spools/cable management system may be motor powered ormanually powered (ratchet arrangement, etc.). FIG. 29 illustratesarticulation of the surgical end effector 1000 through a firstarticulation plane relative to the elongate shaft assembly 2000. FIG. 30illustrates articulation of the surgical end effector 1000 through asecond articulation plane relative to the elongate shaft assembly 2000.FIG. 31 illustrates articulation of the surgical end effector 1000through multiple articulation planes relative to the elongate shaftassembly 2000.

FIGS. 32-34 illustrate an alternative articulation joint 2200′ in theform of an elastomeric joint assembly 2210′. As can be seen in FIG. 33,each articulation cable passes through a corresponding spring 2215′ thatis mounted in the ribs 2216′ of the elastomeric joint assembly 2210′.For example, cable 2242 extends through spring 2244. Cable 2246 extendsthrough spring 2248. Cable 2250 extends through spring 2252 and cable2254 extends through spring 2256. As indicated above, the end effectoris articulated by pulling on and relaxing the appropriate cables 2242,2246, 2250 and 2254. To achieve higher articulation angles with greaterjoint stability, each of the springs 2244, 2248, 2252, and 2256 canslide through the ribs of the elastomeric joint to push the end effectorand pull on the cables extending therethrough. The springs 2244, 2248,2252, and 2256 will also retract into the ribs when the cables 2242,2246, 2250, and 2254 are pulled tight. Each of the springs 2244, 2248,2252, and 2256 loosely seat over the particular cable that passestherethrough. Each cable and corresponding spring may terminate orotherwise be coupled to a corresponding solid rod that is supported inthe elongate shaft assembly 2000 and may be pushed and pulled from itsproximal end. When the cable is pulled, the corresponding spring wouldcarry little to no load. When the spring is pushed, the cable wouldcarry little load, but will help limit the end effector movement. Thisinteraction between the cable and spring may facilitate higherarticulation angles that may approach ninety degrees, for example.

Because the radially/longitudinally segmented power screw nutarrangement disclosed herein does not have the same constraints as athree hundred sixty degree nut, the upper vertebra members 2420 in theupper series 2410 and the lower vertebra members 2520 in the lowerseries 2510 are constrained to ensure that their loads are transferredto the firing member in a longitudinal direction. To maintain each ofthe upper vertebra members 2420 in the desired orientation and toprevent the upper vertebra members 2420 from becoming snagged ordisoriented when traversing through the articulation joint 2200, theupper vertebra members 2420 are aligned to pass through an upper sleeve2470 that extends through an upper portion of the outer elastomericjoint assembly 2210 of the articulation joint 2200. See FIGS. 27, 28,and 35. A distal end 2472 of the upper sleeve 2470 is supported in theproximal end 1112 of the elongate channel 1110 and a proximal end 2474of the upper sleeve 2470 is supported in the distal end of the proximalsupport shaft 2120. The upper sleeve 2470 is fabricated from a polymeror plastic material that has a low coefficient of friction and isflexible to enable the upper sleeve 2470 to flex with the outerelastomeric joint assembly 2210. The upper sleeve 2470 protects theupper vertebra members 2420 from contacting the outer elastomeric jointassembly 2210 that is fabricated from an elastomeric material that mayhave a higher coefficient of friction than the coefficient of frictionof the material of the upper sleeve 2470. Stated another way, the uppersleeve 2470 forms a low friction, flexible, continuous, uninterrupted,and fully encapsulating path for the upper vertebra members 2420 as theytraverse the articulation joint 2200.

Similarly, a lower sleeve 2570 is employed to support the lower vertebramembers 2520 as they pass through the articulation joint 2200. A distalend 2572 of the lower sleeve 2570 is supported in the proximal end ofthe elongate channel and a proximal end of the lower sleeve 2570 issupported in the distal end of the proximal support shaft 2120. Like theupper sleeve 2470, the lower sleeve 2570 is fabricated from a polymer orplastic material that has a low coefficient of friction and is flexibleto enable the lower sleeve 2570 to flex with the outer elastomeric jointassembly 2210. The lower sleeve 2570 protects the lower vertebra members2520 from contacting the outer elastomeric joint assembly 2210 as theypass through the articulation joint 2200. Stated another way, the lowersleeve 2570 forms a low friction, flexible, continuous, uninterrupted,and fully encapsulating path for the lower vertebra members 2520 as theytraverse the articulation joint 2200. In various embodiments, the uppersleeve 2470 and the lower sleeve 2570 are configured to bend freelywithout creating a kink. To prevent the formation of kinks in thesleeves, in at least one arrangement, the sleeves 2470, 2570 aresupported within the outer elastomeric joint assembly 2210 such that thesleeves may move axially. For example, when the articulation jointangles up, the lower sleeve 2570 may slide distally and have a largebend radius; the upper sleeve 2470 in the same example, may slideproximally and have a tighter bend radius. By moving axially, the amountof material exposed outside of the joint assembly 2210 which mightotherwise be susceptible to kinking under a tight bend radius isreduced. In at least one arrangement, the distal end 2472 of the uppersleeve 2470 is formed with an upper scoop 2476 that is configured tofunnel the upper vertebra members 2420 into the anvil cap 1260.Similarly, the distal end of the lower sleeve 2570 may be formed with alower scoop that is configured to funnel the lower vertebra members 2520into the channel slot 1140 in the elongate channel 1110.

As indicated above, the anvil mounting portion 1230 comprises a pair oflaterally extending mounting pins 1232 that are configured to bereceived in corresponding mounting cradles or pivot cradles 1120 thatare formed in the proximal end 1112 of the elongate channel 1110. Themounting pins 1232 are pivotally retained within the mounting cradles1120 by an anvil cap 1260 that is attached to the proximal end 1112 ofthe elongate channel 1110 in the above-described manners. The anvil cap1260 comprises a proximal end 1262 and a distal end 1264 and has akeyhole-shaped vertebra passage 1266 extending therethrough toaccommodate passage of the top firing member feature 2320 and uppervertebra members 2420 therethrough. FIG. 36 illustrates the vertebrapassage 1266 in the anvil cap 1260. When the rotary drive screw 2700applies load to the upper vertebra members 2420, the vertebra members2420 will tend to tilt about the area A in FIG. 37, so the uppervertebra member tooth 2450 is no longer square with the rotary drivescrew 2700 and may instead experience a higher-pressure line contact.Areas B in FIG. 37 show where the upper vertebra member 2420 stopstilting. To ensure that most of the loads stay in the longitudinaldirection to perform useful work, the upper vertebra member tooth 2450must be angled the same amount as the upper vertebra member 2420 tilts.Thus, when the upper vertebra member 2420 tilts, the upper vertebramember tooth 2450 will still maintain surface contact with the helicaldrive member 2710 on the rotary drive screw 2700 and all loads will bedirected longitudinally and not vertically. The slightly angled uppervertebra member tooth 2450 may behave like a square thread when thevertebra member 2420 is tilted and better distributes loads to lower thepressure contact. By directing most of the loads in the longitudinaldirection, vertical loads are avoided which could result in theestablishment of friction that would counter the longitudinal loads. Theupper vertebra members 2420 react similarly as they pass down thekeyhole-shaped anvil slot 1240. Likewise, the lower vertebra members2520 react similarly as they pass through the keyhole-shaped axiallyextending channel slot 1140 in the elongate channel 1110.

In the illustrated arrangement, the anvil 1210 is moved to the openposition by a pair of anvil springs 1270 that are supported within theproximal end of the elongate channel. See FIGS. 38, 42, and 43. Thesprings 1270 are positioned to apply a pivotal biasing force tocorresponding anvil control arms 1234 that may be integrally formed withanvil mounting portion 1230 and extend downwardly therefrom. See FIG.38.

FIGS. 39-41 illustrate portions of the anvil 1210, the firing member2310, and the anvil cap 1260 when the anvil 1210 is open (FIG. 39), whenthe anvil 1210 is partially closed (FIG. 40) and after the firing memberhas been advanced distally from the home or starting position (FIG. 41).As can be seen in FIG. 39, when the firing member 2310 is in the home orstarting position, the top firing member feature 2320 is completelyreceived within the vertebra passage 1266 in the anvil cap 1260. Duringa firing stroke, the top firing member feature 2320 and the uppervertebra members 2420 in the upper series 2410 must transition from thevertebra passage 1266 in the anvil cap 1260 to the keyhole-shaped anvilslot 1240. Thus, it is desirable to minimize any gap “G” between theanvil mounting portion 1230 and a distal end 1264 of the anvil cap 1260.To minimize this gap G while facilitate unimpeded pivotal travel of theanvil 1210, the distal end 1264 of the anvil cap 1260 is formed with acurved cap surface 1265 that matches a curved mating surface 1231 on theanvil mounting portion 1230. Both surfaces 1265, 1231 are curved andconcentric about the pivot axis PA or some other reference point. Sucharrangement allows the anvil 1210 to move radially and not interferewith the anvil cap 1260 while maintaining a minimal gap G therebetween.The gap G between the anvil mounting portion 1230 and the distal end1264 of the anvil cap 1260 is significantly shorter than a length of anupper vertebra member 2420 which facilitates easy transition of eachupper vertebra member 2420 from the vertebra passage 1266 in the anvilcap 1260 to the keyhole-shaped anvil slot 1240. In addition, to furtherassist with the transition of the top firing member feature 2320 intothe keyhole-shaped anvil slot 1240, a ramped surface 1241 is formedadjacent the curved mating surface 1231 on the anvil mounting portion1230. As the firing member 2310 is initially advanced distally from thehome or starting position, a distal end of the top firing member feature2320 contacts the ramped surface 1241 and begins to apply a closingmotion to the anvil 1210 as can be seen in FIG. 40. Further distaladvancement of the firing member 2310 during the firing stroke or firingsequence causes the top firing member feature to enter the keyholeshaped anvil slot 1240 to completely close the anvil 1210 and retain theanvil 1210 in the closed position during the firing sequence. See FIG.41.

In general, the highest firing forces established in an endocutter areassociated with cutting and stapling tissue. If those same forces can beused to close the anvil, then the forces generated during pre-clampingand grasping of tissue can be high as well. In at least one arrangement,the firing member body 2312 further comprises a firing member wing ortab 2355 that extends laterally from each lateral side of the firingmember body 2312. See FIGS. 15 and 36. The firing member wings 2355 arepositioned to contact the corresponding anvil control arms 1234 when thefiring member 2310 is driven in the proximal direction PD from the homeor starting position to quickly close the anvil 1210 for graspingpurposes. In at least one arrangement, when the firing member 2310 is inthe home or starting position, the firing member wings 2355 are locateddistal to the anvil control arms 1234 as shown in FIG. 42. When thefiring member 3210 is moved proximally, the firing member wings 2355push the anvil control arms 1234 (pivotal direction C) against the biasof the anvil springs 1270. See FIG. 42. In one arrangement, the firingmember 2310 only has to move a short distance D to pivot the anvil 1210to a closed position. In one embodiment, distance D may be approximately0.070 inches long, for example. This short movement allows for a quickresponse. Because the anvil pivot point or pivot axis PA is relativelyfar from the firing member wings 2355 which creates a substantial momentarm, the proximal movement of the firing member 2310 (and firing memberwings 2355) results in an application of high pre-compression torque tothe anvil 1210 to move the anvil 1210 to a closed position. Thus, thefiring member wings 2355 may be referred to herein as “pre-compressionfeatures”. See FIG. 43. Thus, the clinician may use the surgical endeffector 1000 to grasp and manipulate tissue between the anvil 1210 andthe surgical staple cartridge 1300 without cutting the tissue andforming the staples, by advancing the firing member 2310 proximally theshort distance D to cause the anvil 1210 to quickly pivot to a closedposition.

The firing member 2310 may be moved in the proximal direction PD byrotating the rotary drive screw 2700 in a second rotary direction. Thus,when the firing member 2310 is in the “home” or starting position, theanvil 1210 may be biased into the fully open position by the anvilsprings 1270. Activation of the rotary drive system 2600 to apply arotary motion to the rotary drive screw 2700 in a first rotary directionwill cause the firing member 2310 to be advanced distally from the homeor starting position to apply an anvil closure motion to the anvil 1210to move the anvil closed to clamp the target tissue between the anvil1210 and the surgical staple cartridge 1300. Continued rotation of therotary drive screw in the first rotary direction will cause the firingmember 2310 to continue to distally advance through the surgical endeffector 1000. As the firing member 2310 moves distally, the firingmember 2310 contacts a sled 1312 (FIG. 19) that is supported in thesurgical staple cartridge 1300 and drives the sled 1312 distally throughthe staple cartridge body 1302. When the firing member 2310 is in thehome or starting position, the surgeon may wish to use the surgical endeffector to grasp and manipulate tissue. To do so, the rotary drivesystem is actuated to apply a second rotary drive motion to the rotarydrive screw 2700 in a second rotary direction that is opposite to thefirst rotary direction. Such rotary movement of the rotary drive screw2700 in the second rotary direction will drive the firing member 2310proximally from the starting position and cause the anvil 1210 toquickly pivot to the closed position. Thus, in accordance with at leastone embodiment, the “home or starting position” of the firing member2310 is not its proximal-most position.

If during the firing process, the rotary drive system 2600 quitsrotating, the firing member 2310 may become stuck within the surgicalend effector. In such instance, the top firing member feature 2320 mayremain engaged with the anvil 1210 and the bottom firing member feature2350 may remain engaged with the elongate channel 1110 and therebyprevent the surgeon from moving the anvil 1210 to an open position torelease the tissue clamped between anvil 1210 and surgical staplecartridge 1300. This could occur, for example, if the motor or othercontrol arrangement supplying the rotary drive motions to the rotarydrive shaft 2610 fails or otherwise becomes inoperative. In suchinstances, the firing member 2310 may be retracted back to the home orstarting position within the surgical end effector 1000 by pulling thetop cable 2404 and the lower cable 2504 in a proximal direction. Forexample, a proximal portion of the top cable 2404 and a proximal portionof the lower cable 2505 may be spooled on a rotary spool orcable-management system 2009 (FIG. 2) in the housing portion of thesurgical instrument 10 that is configured to payout the top cable 2404and lower cable 2504 during the firing stroke and also retract thecables 2404, 2504 in a proximal direction should the firing member 2310need to be retracted. The cable management system 2009 may be motorpowered or manually powered (ratchet arrangement, etc.) to applyretraction motions to the cables 2404, 2504. When the cables 2404, 2504are retracted, the upper vertebra members 2420 and lower vertebramembers 2520 will cause the rotary drive screw 2700 to spin in reverse.

The following equation may be used to determine whether the rotary drivescrew 2700 will spin in reverse depending upon the lead (L), pitchdiameter (d_(r)), tooth angle (α) and friction (μ):

$\mu \geq {\frac{L}{\pi d_{p}}\cos\;\alpha}$

The rotary drive screw 2700 may self-lock if the above equation is true.For the most part, in many instances, the pitch diameter is mostly fixedfor an endocutter, but the lead and tooth angle are variable. Becausethe upper vertebra member teeth 2450 and lower vertebra member teeth2550 are mostly square, the rotary drive screw 2700 is more likely to beback drivable (cos(90)=1). The leads of the upper vertebra member teeth2450 and lower vertebra member teeth 2550 may also be advantageous inthat the rolling friction between the vertebra members 2420, 2520 andthe rotary drive screw 2700 is more likely to enable the rotary drivescrew 2700 to be back driven. Thus, in the event of an emergency, thesurgeon can pull on the upper and lower cables 2404, 2504 in theproximal direction to cause the firing member 2310 to fully retract fora quick “bailout”.

As indicated above, the relative control motions for the rotary drivesystem 2600, as well as the various cable-management systems employed inconnection with the firing system 2300 and the articulation controlsystem 2240, may be supported within a housing 2002 which may behandheld or comprise a portion of a larger automated surgical system.The firing system 2300, articulation control system 2240, and the rotarydrive system 2600 may, for example, be motor-controlled and operated byone or more control circuits.

One method of using the surgical instrument 10 may involve the use ofthe surgical instrument 10 to cut and staple target tissue within apatient using laparoscopic techniques. For example, one or more trocarsmay have been placed through the abdominal wall of a patient to provideaccess to a target tissue within the patient. The surgical end effector1000 may be inserted through one trocar and one or more cameras or othersurgical instruments may be inserted through the other trocar(s). Toenable the surgical end effector 1000 to pass through the trocarcannula, the surgical end effector 1000 is positioned in anunarticulated orientation and the jaws 1100 and 1200 must be closed. Toretain the jaws 1100 and 1200 in the closed position for insertionpurposes, for example, the rotary drive system 2600 may be actuated toapply the second rotary motion to the rotary drive screw 2700 to causethe firing member 2310 to move proximally from the starting position tomove the anvil 1210 (jaw 1200) to the closed position. See FIG. 44. Therotary drive system 2600 is deactivated to retain the firing member 2310in that position. Once the surgical end effector has passed into theabdomen through the trocar, the rotary drive system 2600 may beactivated to cause the rotary drive screw 2700 to drive the firingmember 2310 distally back to the starting position wherein the anvilsprings 1270 will pivot the anvil 1210 to the open position. See FIG.38.

Once inside the abdomen and before engaging the target tissue, thesurgeon may need to articulate the surgical end effector 1000 into anadvantageous position. The articulation control system 2240 is thenactuated to articulate the surgical end effector in one or more planesrelative to a portion of the elongate shaft assembly 2000 that isreceived within the cannula of the trocar. Once the surgeon has orientedthe surgical end effector 1000 in a desirable position, the articulationcontrol system 2240 is deactivated to retain the surgical end effector1000 in the articulated orientation. The surgeon may then use thesurgical end effector to grasp the target tissue or adjacent tissue byactivating the rotary drive system to rotate the rotary drive screw inthe second rotary direction to move the firing member proximally tocause the anvil 1210 to rapidly close to grasp the tissue between theanvil 1210 and the surgical staple cartridge 1300. The anvil 1210 may beopened by reversing the rotation of the rotary drive screw 2700. Thisprocess may be repeated as necessary until the target tissue has beproperly positioned between the anvil 1210 and the surgical staplecartridge 1300.

Once the target tissue has been positioned between the anvil 1210 andthe surgical staple cartridge, the surgeon may commence the closing andfiring process by activating the rotary drive system 2600 to drive thefiring member 2310 distally from the starting position. As the firingmember 2310 moves distally from the starting position, the firing member2310 applies a closure motion to the anvil 1210 and moves the anvil 1210from the open position to the closed position in the manners discussedabove. As the firing member 2310 moves distally, the firing member 2310retains the anvil 1210 in the closed position thereby clamping thetarget tissue between the anvil 1210 and the surgical staple cartridge1300. As the firing member 2310 moves distally, the firing member 2310contacts a sled 1312 supported in the surgical staple cartridge 1300 andalso drives the sled 1312 distally through the staple cartridge body1302. The sled 1312 serially drives rows of drivers supported in thestaple cartridge toward the clamped target tissue. Each driver hassupported thereon one or more surgical staples or fasteners which arethen driven through the target tissue and into forming contact with theunderside of the anvil 1210. As the firing member 2310 moves distally,the tissue cutting edge 2314 thereon cuts through the stapled tissue.

After the firing member 2310 has been driven distally to the endingposition within the surgical end effector 1000 (FIG. 45), the rotarydrive system 2600 is reversed which causes the firing member 2310 toretract proximally back to the home or starting position. Once thefiring member 2310 has returned to the starting position, the anvilsprings 1270 will pivot the anvil 1210 to the open position to enablethe surgeon to release the stapled tissue from the surgical end effector1000. Once the stapled tissue has been released, the surgical endeffector may be withdrawn out of the patient through the trocar cannula.To do so, the surgeon must first actuate the articulation control system2240 to return the surgical end effector 1000 to an unarticulatedposition and actuate the rotary drive system to drive the firing member2310 proximally from the home or starting position to close the jaws.Thereafter, the surgical end effector 1000 may be withdrawn through thetrocar cannula. If during the firing process or during the retractionprocess, the firing system becomes inoperative, the surgeon may retractthe firing member 2310 back to the starting position by applying apulling motion to the cables 2404, 2505 in the proximal direction in thevarious manners described herein.

FIGS. 46-68 illustrate another surgical instrument 22010 that in manyaspects is identical or very similar to the surgical instrument 10described above, except for the various differences discussed below.Like surgical instrument 10, surgical instrument 22010 may address manyof the challenges facing surgical instruments with articulatable endeffectors that are configured to cut and fasten tissue. In variousembodiments, the surgical instrument 22010 may comprise a handhelddevice. In other embodiments, the surgical instrument 22010 maycomprises an automated system sometimes referred to as arobotically-controlled system, for example. In various forms, thesurgical instrument 22010 comprises a surgical end effector 23000 thatis operably coupled to an elongate shaft assembly 24000. The elongateshaft assembly 24000 may be operably attached to a housing that ishandheld or otherwise comprises a portion of a robotic system as wasdiscussed above.

As can be seen in FIG. 49, in one form, the surgical end effector 23000comprises a first jaw 23100 and a second jaw 23200. In the illustratedarrangement, the first jaw 23100 comprises an elongate channel 23110that comprises a proximal end 23112 and a distal end 23114 and isconfigured to operably support a surgical staple cartridge 1300 therein.The elongate channel 23110 has an open bottom to facilitate ease ofassembly and has a channel cover 23113 that is configured to be attachedthereto (welded, etc.) to cover the opening and add rigidity to theelongate channel 23110. In the illustrated arrangement, the second jaw23200 comprises an anvil 23210 that comprises an elongate anvil body23212 that comprises a proximal end 23214 and a distal end 23216. In onearrangement, an anvil cover 23213 is provided to facilitate assembly ofthe device and add rigidity to the anvil 23210 when it is attached(welded, etc.) to the anvil body 23212. The anvil body 23212 comprises astaple-forming undersurface 23218 that faces the first jaw 23100 and mayinclude a series of staple-forming pockets (not shown) that correspondsto each of the staples or fasteners in the surgical staple cartridge1300. The proximal end 23214 of the anvil body 23212 comprises an anvilmounting portion 23230 that includes a pair of laterally extendingmounting pins 23232 that are configured to be received in correspondingmounting cradles or pivot cradles 23120 formed in the proximal end 23112of the elongate channel 23110. The mounting pins 23232 are pivotallyretained within the mounting cradles 23120 by an anvil cap 23260 thatmay be attached to the proximal end 23112 of the elongate channel 23110by screws 23261. In other arrangements, the anvil cap 23260 may beattached to the elongate channel 23110 by welding, adhesive, etc. Sucharrangement facilitates pivotal travel of the anvil 23210 relative tothe surgical staple cartridge 1300 mounted in the elongate channel 23110about a pivot axis PA between an open position (FIG. 47) and a closedposition (FIG. 48). Such pivot axis PA may be referred to herein asbeing “fixed” in that the pivot axis does not translate or otherwisemove as the anvil 23210 is pivoted from an open position to a closedposition.

In the illustrated arrangement, the anvil 23210 is moved to the openposition by a pair of anvil springs 23270 that are supported within theproximal end 23112 of the elongate channel 23110. See FIGS. 49 and 62.The springs 23270 are positioned to apply a pivotal biasing force tocorresponding portions of the anvil 23210 to apply opening forcesthereto. See FIG. 47.

In the illustrated arrangement, the elongate shaft assembly 24000defines a shaft axis SA and comprises a proximal shaft portion 24100that may operably interface with a housing of the control portion (e.g.,handheld unit, robotic tool driver, etc.) of the surgical instrument22010. The elongate shaft assembly 24000 further comprises anarticulation joint 24200 that is attached to the proximal shaft portion24100 and the surgical end effector 23000. In various instances, theproximal shaft portion 24100 comprises a hollow outer tube 24110 thatmay be operably coupled to a housing in the various manners discussedabove. As can be seen in FIG. 49, the proximal shaft portion 24100 mayfurther comprise a rigid proximal support shaft 24120 that is supportedwithin the hollow outer tube 24110 and extends from the housing to thearticulation joint 24200. The rigid proximal support shaft 24120 maycomprise a first half 24120A and a second half 24120B that may becoupled together by, for example, welding, adhesive, etc. The rigidproximal support shaft 24120 comprises a proximal end 24122 and a distalend 24124 and includes an axial passage 24126 that extends therethroughfrom the proximal end 24122 to the distal end 24124.

As was discussed above, many surgical end effectors employ a firingmember that is pushed distally through a surgical staple cartridge by anaxially movable firing beam. The firing beam is commonly attached to thefiring member in the center region of the firing member body. Thisattachment location can introduce an unbalance to the firing member asit is advanced through the end effector. Such unbalance can lead toundesirable friction between the firing member and the end effectorjaws. The creation of this additional friction may require anapplication of a higher firing force to overcome such friction as wellas can cause undesirable wear to portions of the jaws and/or the firingmember. An application of higher firing forces to the firing beam mayresult in unwanted flexure in the firing beam as it traverses thearticulation joint. Such additional flexure may cause the articulationjoint to de-articulate—particularly when the surgical end effector isarticulated at relatively high articulation angles. The surgicalinstrument 22010 employs a firing system 24300 that is identical to orvery similar in many aspects as firing system 2300 described above. Assuch, only those aspects of the firing system 24300 needed to understandthe operation of the surgical instrument 22010 will be discussed below.

As can be seen in FIGS. 50-54, in at least one embodiment, the firingsystem 24300 comprises a firing member 24310 that includes avertically-extending firing member body 24312 that comprises a topfiring member feature 24320 and a bottom firing member feature 24350. Atissue cutting blade 24314 is attached to or formed in thevertically-extending firing member body 24312. See FIGS. 50 and 51. Inat least one arrangement, it is desirable for the firing member 24310 topass through the anvil body 23212 with low friction, high strength andhigh stiffness. In the illustrated arrangement, the top firing memberfeature 24320 comprises a T-shaped body 24322 that has two laterallyextending tabs 24323 protruding therefrom and a top axial passage 24324extending therethrough. See FIG. 53. The bottom firing member feature24350 comprises a T-shaped body 24352 that has two laterally extendingtabs 24353 protruding therefrom and a bottom axial passage 24354extending therethrough. See FIG. 50. In at least one arrangement, thetop firing member feature 24320 and the bottom firing member feature24350 are integrally formed with the vertically-extending firing memberbody 24312. As can be seen in FIG. 54, the anvil body 23212 comprises anaxially extending anvil slot 23240 that defines two opposed ledges 23241for slidably receiving the laterally extending tabs 24323 thereon.Similarly, the elongate channel 23110 comprises an axially extendingchannel slot 23140 that defines axially extending channel ledges 23141that are configured to slidably receive the laterally extending tabs24353 thereon.

In the illustrated arrangement, the firing system 24300 comprises anupper flexible spine assembly 24400 that is operably coupled to the topfiring member feature 24320 of the firing member 24310. In at least oneembodiment, the upper flexible spine assembly 24400 comprises an upperseries 24410 of upper vertebra members 24420 that are loosely coupledtogether by an upper flexible coupler member 24440 that extends througheach of the upper vertebra members 24420 and is attached to the topfiring member feature 24320.

As can be seen in FIG. 52, each upper vertebra member 24420 issubstantially T-shaped when viewed from an end thereof. In one aspect,each upper vertebra member 24420 comprises an upper vertebra bodyportion 24422 that has a proximal end 24424 and a distal end 24428. Eachupper vertebra member 24420 further comprises a downwardly extendingupper drive feature or upper vertebra member tooth 24450 that protrudesfrom the upper vertebra body portion 24422. Each upper vertebra membertooth 24450 has a helix-shaped proximal upper face portion 24452 and ahelix-shaped distal upper face portion 24454. Each proximal end 24424 ofthe upper vertebra body portions 24422 has an arcuate or slightlyconcave curved shape and each distal end 24428 has an arcuate orslightly convex curved shape. When arranged in the upper series 24410,the convex distal end 24428 on one upper vertebra member 24420 contactsand mates with the concave proximal end 24424 on an adjacent uppervertebra member 24420 in the upper series 24410 to maintain the uppervertebra members 24420 roughly in alignment so that the helix-shapedproximal upper face portion 24452 and a helix-shaped distal upper faceportion 24454 on each respective upper vertebra member tooth 24450 canbe drivingly engaged by a rotary drive screw 2700 in the various mannersdisclosed herein. These curved mating surfaces on the upper vertebramembers 24420 allow the upper vertebras members 24420 to better transferloads between themselves even when they tilt.

In at least one embodiment, an upper alignment member 24480 is employedto assist with the alignment of the upper vertebra members 24420 in theupper series 24410. In one arrangement, the alignment member 24480comprises a spring member or metal cable which may be fabricated fromNitinol wire, spring steel, etc., and be formed with a distal upperlooped end 24482 and two upper leg portions 24484 that extend throughcorresponding upper passages 24425 in each upper vertebra body portion24422. The upper flexible coupler member 24440 extends through an upperpassage 24429 in each of the upper vertebra members 24420 to be attachedto the firing member 24310. In particular, a distal end portion 24442extends through the top axial passage 24324 in the top firing memberfeature 24320 and is secured therein by an upper retention lug 24444. Aproximal portion of the upper flexible coupler member 24440 mayinterface with a corresponding rotary spool or cable-management systemof the various types and designs disclosed herein that serve to payoutand take up the upper flexible coupler member 24440 to maintain adesired amount of tension therein during operation and articulation ofthe surgical end effector 23000. The cable management system may bemotor powered or manually powered (ratchet arrangement, etc.) tomaintain a desired amount of tension in the upper flexible couplermember 24440. The amount of tension in each flexible coupler member mayvary depending upon the relative positioning of the surgical endeffector 23000 to the elongate shaft assembly 24000.

The firing system 24300 further comprises a lower flexible spineassembly 24500 that is operably coupled to the bottom firing memberfeature 24350. The lower flexible spine assembly 24500 comprises a lowerseries 24510 of lower vertebra members 24520 that are loosely coupledtogether by a lower flexible coupler member 24540 that extends througheach of the lower vertebra members 24520 and is attached to the bottomfiring member feature 24350. As can be seen in FIG. 52, each lowervertebra member 24520 is substantially T-shaped when viewed from an endthereof. In one aspect, each lower vertebra member 24520 comprises alower vertebra body portion 24522 that has a proximal end 24524 and adistal end 24528. Each lower vertebra member 24520 further comprises anupwardly extending lower drive feature or lower vertebra member tooth24550 that protrudes from the lower vertebra body portion 24522. Eachlower vertebra member tooth 24550 has a helix-shaped proximal lower faceportion 24552 and a helix-shaped distal lower face portion 24554. Theproximal end 24524 of each lower vertebra body portions 24522 has anarcuate or slightly concave curved shape and each distal end 24528 hasan arcuate or slightly convex curved shape. When arranged in the lowerseries 24510, the convex distal end 24528 on one lower vertebra member24520 contacts and mates with the concave proximal end 24524 on anadjacent lower vertebra member 24520 in the lower series 24510 tomaintain the lower vertebra members 24520 roughly in alignment so thatthe helix-shaped proximal lower face portion 24552 and a helix-shapeddistal lower face portion 24554 on each respective lower vertebra membertooth 24550 can be drivingly engaged by the rotary drive screw 2700 inthe various manners disclosed herein. These curved mating surfaces onthe lower vertebra members 24520 allow the lower vertebra members 24520to better transfer loads between themselves even when they tilt.

In at least one embodiment, a lower alignment member 24580 is employedto assist with the alignment of the lower vertebra members 24520 in thelower series 24510. In one arrangement, the lower alignment member 24580comprises a spring member or metal cable which may be fabricated fromNitinol wire, spring steel, etc., and be formed with a distal lowerlooped end 24582 and two lower leg portions 24584 that extend throughcorresponding lower passages 24525 in each lower vertebra body portion24522. The lower flexible coupler member 24540 extends through thebottom axial passage 24529 in each of the lower vertebra members 24520to be attached to the firing member 24310. In particular, a distal endportion 24542 of the lower flexible coupler member 24540 extends throughthe bottom axial passage 24354 in the bottom firing member feature 24350and is secured therein by a lower retention lug 24544. A proximalportion of the lower flexible coupler member 24540 may interface with acorresponding rotary spool or cable-management system of the varioustypes and designs disclosed herein that serve to payout and take up thelower flexible coupler member 24540 to maintain a desired amount oftension therein during operation and articulation of the surgical endeffector 23000. The cable management system may be motor powered ormanually powered (ratchet arrangement, etc.) to maintain a desiredamount of tension in the lower flexible coupler member 24540. The amountof tension in each flexible coupler member may vary depending upon therelative positioning of the surgical end effector 23000 to the elongateshaft assembly 24000.

In accordance with at least one aspect, a large surface area isadvantageous for distributing the force between the vertebra memberswhen they push so that the vertebra members cannot twist relative toeach other. The available area in the anvil and channel is limited andthe anvil and channel must remain stiff. The T-shaped upper vertebramembers 24420 and the T-shaped lower vertebra members 24520 are designedto fit in the limited spaces available in the anvil 23210 and theelongate channel 23110 while ensuring that there is a large amount ofarea to distribute the firing loads. The curved surfaces on each uppervertebra member 24420 and each lower vertebra member 24520 allow each ofthose vertebras to better transfer loads between themselves even whenthey tilt. The upper alignment member 24480 and the lower alignmentmember 24580 may also serve to prevent the upper vertebra members 24420and the lower vertebra members 24520 from twisting relative to eachother. The large surface area may also help to prevent galling of thevertebra members and/or the anvil and channel. The upper flexible spineassembly 24400 and the lower flexible spine assembly 24500 otherwiseoperably interface with the rotary drive screw 2700 arrangements asdisclosed herein. The upper flexible coupler member 24440 and the lowerflexible coupler member 24540 may also be used in the manners discussedabove to retract the firing member 24310 back to its starting positionif, during a firing stroke, the firing drive system 24300 fails.

As can be seen in FIG. 51, the top firing member feature 24320 on thefiring member 24310 comprises a distal upper firing member tooth segment24330 that is equivalent to one half of an upper vertebra member tooth24450 on each upper vertebra member 24420. In addition, two proximalupper firing member teeth 24336 that are identical to an upper vertebramember tooth 24450 on each upper vertebra member 24420 are spaced fromthe distal upper firing member tooth segment 24330. The distal upperfiring member tooth segment 24330 and the proximal upper firing memberteeth 24336 may each be integrally formed with the top firing memberfeature 24320 of the firing member 24310. Likewise, the bottom firingmember feature 24350 of the firing member 24310 comprises a distal lowerfiring member tooth 24360 and two proximal lower firing member teeth24366 that are integrally formed on the bottom firing member feature24350. For example, in at least one arrangement, the firing member 24310with the rigidly attached teeth 24330, 24336, 24360, and 24366 may befabricated at one time as one unitary component using conventional metalinjection molding techniques. The person of ordinary skill in the artwill recognize that the firing member 24310 operates in essentially thesame manner as the firing member 2310 as was described in detail herein.

Turning now to FIGS. 55-58, in accordance with at least one aspect, thearticulation joint 24200 comprises a movable exoskeleton assembly 24800.In one form, the movable exoskeleton assembly 24800 comprises a series24802 of movably interfacing annular rib members 24810. As can be seenin FIGS. 55-57, each annular rib member 24810 comprises a first orproximal face 24820 that comprises a convex or domed portion 24822. Eachannular rib member 24810 further comprises a second or distal face 24830that is concave or dished. Each annular rib member 24810 furthercomprises an upper spine passage 24840 that is configured to accommodatepassage of the upper flexible spine assembly 24400 therethrough and alower spine passage 24842 that is configured to accommodate passage ofthe lower flexible spine assembly 24500 therethrough. In addition, eachannular rib member 24810 further comprises four articulation passages24850, 24852, 24854, and 24856 to accommodate passage of articulationactuators in the form of articulation cables 24242, 22446, 24250, and24254 therethrough. See FIG. 49. Each annular rib member 24810 furthercomprises a central drive passage 24860 that is configured toaccommodate passage of the constant velocity (CV) drive shaft assembly2620 therethrough.

As can be seen in FIG. 58, the movable exoskeleton assembly 24800comprises a proximal attachment rib 24870 that is configured to attachthe movable exoskeleton assembly 24800 to the distal end 24124 of theproximal support shaft 24120 by cap screws 24880 or other suitablefastener arrangements. The proximal attachment rib 24870 comprises afirst or distal face 24872 that is concave or dished to receive ormovably interface with the convex or domed portion 24822 of the proximalface 24820 of a proximal-most annular rib member 24810P. Similarly, themovable exoskeleton assembly 24800 comprises a distal attachment rib24890 that is configured to attach the movable exoskeleton assembly24800 to the proximal end 23112 of the elongate channel 23110 by capscrews 24882 or other suitable fasteners. The distal attachment rib24890 comprises a first or proximal face 24892 that comprises a convexor domed portion 24894 that configured to be received in or movablyinterface with the concave or dished distal face 24832 of a distal-mostannular rib member 24810D. In various embodiments, the annular ribmembers 24810, 24810P, and 24810D may be fabricated from any suitablemetal (e.g., stainless steel, titanium, etc.) or other suitablematerial. The annular rib members 24810, 24810P, and 24810D may beformed by suitable drawing or forming operations, by machining orcasting. The proximal faces 24820 and the distal faces 24830 may bepolished or otherwise finished to a desirable smooth finish to reducefriction and facilitate movement between the annular rib members 24810,24810P, and 24810D. In accordance with one aspect, all edges on eachannular rib member 24810, 24810P, 24810D are rounded to facilitaterelative movement between the annular rib members. The proximalattachment rib 24870 and the distal attachment rib 24890 may be formedwith similar attributes.

The surgical instrument 22010 also comprises an articulation system24240 that is configured to apply articulation motions to the surgicalend effector 23000 to articulate the surgical end effector 23000relative to the elongate shaft assembly 24000. In at least onearrangement, for example, as mentioned above, the articulation system24240 comprises four articulation cables 24242, 24246, 24250, and 24254that extend through the elongate shaft assembly 2400. See FIG. 49. Inthe illustrated arrangement, the articulation cables 24242, 24246 passthrough the proximal attachment rib 24870 and through each of theannular rib members 24810P, 24810, and 24810D to be secured to thedistal attachment rib 24890. In one arrangement for example, each of thearticulation cables 24242, 24246 are secured to the distal attachmentrib 24890 by corresponding attachment lugs 24243. See FIGS. 61 and 63.Likewise, the articulation cables 24250 and 24254 extend through theproximal attachment rib 24870 and through each of the annular ribmembers 24810P, 24810, and 24810D to be secured to the distal attachmentrib 24890 by corresponding attachment lugs 24243.

In one arrangement, each of the articulation cables 24242, 24246, 24250,and 24254 extend through corresponding coil springs 24896 that aresupported in cavities 24125 in the distal end 24124 of the rigidproximal support shaft 24120. In addition, each coil spring 24896 isassociated with a tensioning lug 24897 that is also journaled onto eachrespective articulation cable 24242, 24246, 24250, and 24524 and issecured thereon to attain a desired amount of compression in each spring24896 which serves to retain the annular rib members 24810P, 24810, and24810D in movable engagement with each other and with the proximalattachment rib 24870 and the distal attachment rib 24890. The cables24242, 24246, 24250, and 24254 operably interface with an articulationcontrol system that is supported in the housing of the surgicalinstrument 22010. For example, as was discussed above, a proximalportion of each cable 24242, 24246, 24250, and 24254 may be spooled on acorresponding rotary spool or cable-management system 2007 (FIG. 2) inthe housing portion of the surgical instrument 22010 that is configuredto payout and retract each cable 24242, 24246, 24250, and 24254 indesired manners. The spools/cable management system may be motor poweredor manually powered (ratchet arrangement, etc.). FIG. 59 illustrates thearticulation joint 24200 in an unarticulated position and FIG. 60illustrates the articulation joint in one articulated configuration.Such arrangement permits the surgical end effector 23000 to bearticulated through multiple articulation planes relative to theelongate shaft assembly 24000.

As can be seen in FIGS. 49, 58, and 64, the surgical instrument 22010employs a constant velocity (CV) drive shaft assembly 2620 that spans orextends axially through the articulation joint 24200. The operation andconstruction of the CV drive shaft assembly 2620 was described in detailabove and will not be repeated here beyond what is necessary tounderstand the operation of the surgical instrument 22010. Briefly asdescribed above, the CV drive shaft assembly 2620 comprises a proximalCV drive assembly 2630 and a distal CV drive shaft 2670. The proximal CVdrive assembly 2630 comprises a proximal shaft segment 2632 thatconsists of an attachment shaft 2634 that is configured to benon-rotatably received within a similarly-shaped coupler cavity 2616 inthe distal end 2614 of the proximal rotary drive shaft 2610. Theproximal shaft segment 2632 operably interfaces with a series 2640 ofmovably coupled drive joints 2650. As can be seen in FIG. 58 as was alsodescribed previously, to ensure that the drive joints 2650 are engagedwith each other, a proximal drive spring 2740 is employed to apply anaxial biasing force to the series 2640 of drive joints 2650. Forexample, as can be seen in FIG. 58, proximal drive spring 2740 ispositioned between the proximal mounting bushing 2734 and a supportflange that is formed between the distal socket portion 2636 and aproximal barrel portion 2638 of the proximal shaft segment 2632. In onearrangement, the proximal drive spring 2740 may comprise an elastomericO-ring received on the proximal barrel portion 2638 of the proximalshaft segment 2632. The proximal drive spring 2740 lightly biases thedrive joints 2650 together to decrease any gaps that occur duringarticulation. This ensures that the drive joints 2650 transfer loadstorsionally. It will be appreciated, however, that in at least onearrangement, the proximal drive spring 2740 does not apply a high enoughaxial load to cause firing loads to translate through the articulationjoint 2200.

To further prevent the drive joints 2650 from buckling duringarticulation, the series 2640 of movably coupled drive joints 2650extend through at least one low friction drive cover 24730 that extendsthrough the central drive passage 24860 in each of the annular ribmembers 24810. In the arrangement depicted in FIGS. 63 and 65, the drivecover 24730 comprises an outer and inner cut hypotube 24732. Suchhypotube 24732 may be fashioned from metal (e.g., stainless steel, etc.)and have multiple series of cuts or slits therein that may be made usinglaser cutter arrangements. In the illustrated arrangement, the hypotube24732 may be fabricated with an upper relief passage 24734 that providesclearance for the upper flexible spine assembly 24400 to pass thereoverduring operation while the surgical end effector 23000 is in anarticulated position and articulated positions. In addition, thehypotube 24732 may have a lower relief passage 24736 to provide similarclearance for the lower flexible spine assembly 24500. As can also beseen in FIG. 65, the hypotube 24732 may be shaped with diametricallyopposed lateral tab portions 24738 to provide lateral stability duringarticulation. FIG. 66 illustrates an alternative drive cover 24730′ thatcomprises an inner cut hypotube 24732′. FIGS. 58, 67, 68, and 69illustrate an alternative drive cover 24730″ that comprises flexibleheat shrink tubing 24732″ that is applied over the constant velocity(CV) drive shaft assembly 2620. In still other arrangements, the drivecover may comprise a coiled spring or coiled member as well.

Various embodiments of the present disclosure provide advantages overprevious surgical endocutter configurations that are capable ofarticulation. For example, pushing a firing member forward in anarticulating end effector generally requires a lot of force and thatforce must be balanced. For example, when firing the firing member at anangle of greater than sixty degrees, it becomes very difficult to push abeam through the articulation joint. The joint also experiencessignificant loads which may cause the articulation joint tode-articulate. By employing an upper flexible drive arrangement and alower flexible drive arrangement that are each flexible through thearticulation joint, but then become rigid when they are distal to thearticulation joint can allow for a large degree of articulation (e.g.,articulation angles over seventy degrees) while applying balanced loadsto the firing member that are constrained to the firing member and notto the articulation joint. Stated another way, torsional loads areapplied proximal to the articulation joint instead of longitudinal loadswhich could lead to de-articulation of the end effector. The torsionalloads are converted to longitudinal loads at a position that is distalto the articulation joint. Thus, the rotary drive screw serves toactually convert torsional motion or loads to longitudinal loads thatare applied to the firing member at a location that is distal to thearticulation joint.

Further, by longitudinally breaking up the threaded drive arrangements,the threaded drive arrangements pass through the articulation jointwhile also effectively decreasing the length of the surgical endeffector. For example, each single vertebra tooth is significantlyshorter than multiple pitches rigidly connected. The vertebra can angleas they pass through the articulation joint. This flexibleinterconnection enables the rotary drive screw to be closely positionedto the articulation joint as compared to being significantly spacedtherefrom if all of the pitches were rigidly connected.

FIGS. 70-73 illustrate another surgical end effector 4000 that may beemployed with a surgical instrument 3010 that may be similar to thesurgical instrument 10 in many aspects. The surgical end effector 4000may be similar to the surgical end effector 1000 except for thedifferences discussed below. The surgical end effector 4000 is operablycoupled to an elongate shaft assembly 5000. The elongate shaft assembly5000 may be operably attached to a housing portion of the surgicalinstrument 3010. The housing may comprise a handle that is configured tobe grasped, manipulated and actuated by the clinician. In otherembodiments, the housing may comprise a portion of a robotic system thathouses or otherwise operably supports at least one drive system that isconfigured to generate and apply at least one control motion which couldbe used to actuate the surgical end effectors disclosed herein and theirrespective equivalents.

In at least one form, the surgical end effector 4000 comprises a firstjaw 4100 and a second jaw 4200. In the illustrated arrangement, thefirst jaw 4100 comprises an elongate channel 4110 that comprises aproximal end 4112 and a distal end 4114 and is configured to operablysupport a surgical staple cartridge 1300 therein. In the illustratedarrangement, the second jaw 4200 comprises an anvil 4210 that may besimilar to anvil 1210 described above. In the illustrated arrangement,the elongate shaft assembly 5000 defines a shaft axis SA and comprises aproximal shaft segment that operably interfaces with a housing of thecontrol portion (e.g., handheld unit, robotic tool driver, etc.) of thesurgical instrument 3010. The elongate shaft assembly 5000 furthercomprises an articulation joint 5200 that is attached to a proximalshaft portion and the surgical end effector 4000.

The elongate shaft assembly 5000 may comprise a distal spine assembly5010 that is attached to the proximal end 4112 of the elongate channel4110 and the articulation joint 5200. See FIG. 70. The distal spineassembly 5010 is non-movably supported in a distal outer tube segment5020 that operably interfaces with the surgical end effector 4000. Theelongate shaft assembly 5000 further includes a proximal spine member(not shown) that operably interfaces with a proximal end of thearticulation joint 5200 and may be attached to or otherwise operablyinterface with the housing of the surgical instrument 3010. A proximalouter tube segment 5030 extends from the articulation joint 5200 back tothe housing to operably interface therewith.

The surgical instrument 3010 employs a firing drive system 4300 thatcomprises a firing member 4310 that includes a vertically-extendingfiring member body 4312 that comprises a top firing member feature and abottom firing member feature. A tissue cutting blade 4314 is attached toor formed in the vertically-extending firing member body 4312. Thefiring drive system 4300 comprises a rotary drive nut 4400 that isconfigured to rotatably drive a series 4600 of drive components 4610that operably interface with the firing member 4310. The rotary drivenut 4400 comprises a flexible proximal segment 4410 that spans thearticulation joint 5200 and a threaded distal segment 4420 that isdistal to the articulation joint 5200. The threaded distal segment 4420comprises a series of variable pitched threads 4430, with coarse spacing4432 at the proximal end, and tighter spacing 4434 at the distal or exitend. See FIG. 72. The threaded rotary drive nut 4400 comprises aproximal drive gear 4440 that meshingly interfaces with a distal drivegear 4510 that is attached to a rotary drive shaft 4500. See FIG. 70.The rotary drive shaft 4500 may interface with a gearbox/motorarrangement supported in the housing of the surgical instrument 3010.Rotation of the rotary drive shaft 4500 causes the drive nut 4400 torotate about the shaft axis SA.

The rotary drive nut 4400 comprises a proximal segment 4410 and athreaded distal segment 4420. The threaded distal segment 4420 islocated distal to the articulation joint 5200 and is configured tothreadably engage a series 4600 of drive components 4610 that areloosely linked together by flexible tethers 4640. In at least onearrangement, for example, each drive component 4610 comprises avertically extending plate member 4612 that each includes a top end 4614and a bottom end 4618. The top end 4614 includes a top thread segment4616 and the bottom end 4418 includes a bottom thread segment 4620. Thetop thread segment 4616 and the bottom thread segment 4620 areconfigured to threadably engage the threads 4430 of the rotary drive nut4400. The series 4600 of drive components 4610 is configured to flexiblypass through the articulation joint 5200 and into a vertical passage5012 in the distal spine assembly 5010. Rotation of the rotary drive nut4400 in a first rotary direction causes the series 4600 of drivecomponents 4610 to move axially in the distal direction and rotation ofthe rotary drive nut 4400 in a second rotary direction will cause theseries 4600 of drive components 4610 to move axially in the proximaldirection.

Turning to FIG. 72, in at least one arrangement, each drive component4610 further comprises a distally protruding latch feature 4630. Eachlatch feature 4360 is configured to be releasably received in latchingengagement within a latch cavity 4364 that is formed in the adjacentdrive component 4610 that is immediately distal thereto. When the drivecomponents 4610 are latched together, they form an axially rigid series4600AR of drive components for applying an axial drive motion to thefiring member 5310 to drive the firing member 5310 through the surgicalend effector 4000 from a starting to an ending position and then fromthe ending position back to the starting position. As can be seen inFIG. 72, as the drive components 4610 enter the threaded distal segment4420 of the rotary drive nut 4400, they are loosely linked together. Asthe drive components 4610 threadably engage the finely pitched threads4430 in the threaded distal segment 4420 of the rotary drive nut 4400,the latch features 4630 are latchingly received within the correspondinglatch cavity 4364 in the distally adjacent drive component 4610 to formthe axially rigid series 4600AR of drive components 4610. In onearrangement, a distal-most drive component 4610 may be configured tolatchingly engage the firing member 4310 in a similar manner or inalternative arrangements, the distal-most drive component may benon-removably attached to the firing member 4310.

In the illustrated example, the drive components 4610 in the series 4600of drive components are flexibly linked together such that they can moverelative to each other to accommodate the articulation joint and withoutthe need for reinforcing and support plates that are commonly requiredwhen pushing a firing beam through an articulated joint. As the seriesof drive components 4610 enters and is drivingly engaged by the threadeddistal segment 4420 which is distal to the articulation joint, the drivecomponents 4610 form the axially rigid series of drive components fordriving the firing member 4310 through the surgical end effector 4000.The anvil 4210 may be pivoted into an open position by a spring or otherarrangement in the various manners disclosed herein and then closed bythe firing member 4310 as the firing member 4310 is driven distally froma starting position to an ending position in the various mannersdiscussed herein. Other jaw control arrangements may also be employed tocontrol the opening and closing of the jaws.

FIGS. 73-76 illustrate another surgical end effector 6000 that employs adrive system 6300 that comprises a series 6600 of flexibly linked drivecomponents 6610 that can be used to traverse an articulation joint 6200and rigidly advance a firing member 6130 through the surgical endeffector 6000. The surgical end effector 6000 may comprise a channel6010 that is configured to operably support a surgical staple cartridge(not shown) therein. An anvil 6020 may be pivotally coupled to thechannel 6010 and is movable between an open position and a closedposition by the firing member 6130 or other closure system arrangement.The anvil 6020 may be moved to an open position by a spring or otherarrangement in the various manners disclosed herein.

Turning to FIG. 74, in at least one arrangement, each drive component6610 comprises a drive component body 6612 that has a proximal face6614, a distal face 6616, and thread segment 6620 that is formed on abottom surface 6618. Each drive component 6610 further comprises aproximally protruding latch feature 6630. Each latch feature 6630comprises a neck feature 6632 that has a spherical latch head 6634formed on an end thereof. The latch feature 6630 is configured to bemovably received within a latch cavity 6336 that is formed in theadjacent drive component 6610 that is immediately distal thereto. Tofacilitate movable attachment of the drive components 6610 in movableserial arrangement, the spherical latch head 6634 is inserted through atapered passage 6338 in the drive component body 6612 and into the latchcavity 6636. The spherical latch head 6634 is sized and shaped relativeto the latch cavity 6636 to permit relative movement between the drivecomponents 6610 when arranged as shown in FIG. 74. However, when thedrive components are axially aligned such that the distal face 6616 ofone drive component 6610 is in abutting engagement with the proximalface 6614 of the drive component that is immediately distal thereto, thedrive components 6610 form an axially rigid series 6600AR of drivecomponents that can drive the firing member 6130 through the surgicalend effector 6000.

As can be seen in FIG. 73, a flexible rotary drive system 6700 isemployed to drive the series of 6600 drive components 6610. In onearrangement, the flexible rotary drive system 6700 comprises a flexiblerotary drive shaft 6710 that can pass through the articulation joint6210 and includes a rotary drive gear 6720 that is configured tothreadably engage the thread segments 6620 on each drive component 6610.The flexible rotary drive shaft 6710 may be rotated by a motor/geararrangement supported in a housing of a surgical instrument. The portion6600F of the series 6600 of drive components 6610 that is proximal tothe rotary drive gear 6720, remains flexibly linked or “floppy”. As thedrive components 6610 are threadably engaged by the rotary drive gear6720 they are driven through a passage in the channel 6010 that causesthe drive components to form the axially rigid series 6600AR for drivingthe firing member 6130 through the surgical end effector 6000.

Torsional loads that are applied to firing system components as theytraverse the articulation joint are less likely to de-articulate thearticulation joint than axial loads. Various embodiments disclosedherein transfer torsional loads to longitudinal loads in a location thatis distal of the articulation joint. Because the longitudinal loads arecontained in the end effector, de-articulation is prevented. FIG. 77illustrates one firing system 6800 example that can provide suchadvantages. The firing system 6800 comprises a firing member 6810 thatis configured to be operably supported in a surgical end effector in thevarious manners described herein. A flexible spring-like driven member6820 is attached to the firing member 6810. Such flexible, spring-likedriven member 6820 can span an articulation joint area 6840 that canattain relatively large ranges of articulation. The flexible,spring-like driven member 6820 is configured to be driven axially by aflexible, spring-like torsion drive member 6830 that is rotatablysupported to span the articulation joint area 6840. The flexible,spring-like torsion drive member 6830 includes a threaded insert 6832that is configured to threadably engage the spring-like driven member6820 at a location 6841 that is distal to the articulation joint area6840. The flexible, spring-like torsion drive member 6830 may be rotatedby a motor/gear arrangement supported in a housing of a surgicalinstrument. As the flexible, spring-like torsion drive member 6830rotates in a first direction, the flexible, spring-like driven member6820 translates longitudinally to drive the firing member 6810. Rotationof the flexible torsion drive member 6830 in a second direction willcause the flexible, spring-like driven member to move proximally.

FIG. 78 illustrates another firing system 6850 that comprises a firingmember 6860 that is configured to be operably supported in a surgicalend effector in the various manners described herein. The firing member6860 is driven by firing member drive assembly 6861 which comprises aseries 6862 of spherical ball members 6870 that are coupled together bya flexible cable 6872. Such series 6862 of flexible spherical ballmembers 6870 can span an articulation joint area 6840 that can attainrelatively large ranges of articulation. The series 6862 of flexiblespherical ball members 6870 is configured to be driven axially by aflexible torsion drive member 6880 that is rotatably supported to spanan articulation joint area 6890. The flexible torsion drive member 6880includes an insert 6882 that is configured to drivingly engage thespherical ball members 6870 at a location 6892 that is distal to thearticulation joint area 6890. The flexible torsion drive member 6880 maybe rotated by a motor/gear arrangement supported in a housing of asurgical instrument. As the flexible torsion drive member 6880 rotatesin a first direction, the spherical ball members 6870 are drivendistally into contact with each other to form an axially rigid series6862AR that translates longitudinally to drive the firing member 6860distally. Rotation of the flexible torsion drive member 6880 in a seconddirection will cause the series of spherical ball members 6870 to moveproximally.

FIG. 79 illustrates another firing system 6950 that comprises a firingmember 6960 that is configured to be operably supported in a surgicalend effector in the various manners described herein. A laser cut,hypotube driven member 6970 is attached to the firing member 6960. Suchflexible driven member 6970 can span an articulation joint area 6940that can attain relatively large ranges of articulation. The flexibledriven member 6970 is configured to be driven axially by a flexibletorsion drive member 6980 that is rotatably supported to span thearticulation joint area 6940. The flexible torsion drive member 6980includes a threaded insert 6982 that is configured to threadably engagethe laser cuts 6972 on the flexible driven member 6970 at a location6942 that is distal to the articulation joint area 6940. The flexibletorsion drive member 6980 may be rotated by a motor/gear arrangementsupported in a housing of a surgical instrument. As the flexible torsiondrive member 6980 rotates in a first direction, the flexible drivenmember 6970 translates longitudinally to drive the firing member 6960.Rotation of the flexible torsion drive member 6980 in a second directionwill cause the flexible driven member 6970 to move proximally.

Pushing a firing beam forward in an articulating end effector generallyrequires a lot of force and such force needs to be balanced. Forexample, it is generally difficult to push a firing beam through anarticulation joint that has been articulated to angles of greater thansixty degrees. As the firing beam traverses through the articulationjoint, the firing beam can apply significant loads onto the articulationjoint components which can cause the articulation joint tode-articulate. FIGS. 80-84 illustrate a firing drive system 7300 thatcomprises a flexible upper drive band 7320 and a flexible lower driveband 7330 that are attached to a firing member 7310 that is configuredto move within a surgical end effector 7000 between a starting andending position. As can be seen in FIGS. 80-82, the flexible upper driveband 7320 comprises a plurality of spaced upper drive teeth 7322 thatare configured to threadably engage a helical thread 7342 on a rotarydrive nut 7340. Similarly, the flexible lower drive band 7330 comprisesa plurality of spaced lower drive teeth 7332 that are configured tothreadably engage the helical thread 7342 on the rotary drive nut 7340.In at least one arrangement, the flexible upper drive band 7320 and theflexible lower drive band 7330 are formed from a metal material and arewelded to or otherwise attached to the firing member 7310. Sucharrangement serves to balance the firing loads that are applied to thefiring member 7310.

The rotary drive nut 7340 is received on a flexible rotary drive shaft7350 that is centrally disposed between the flexible upper drive band7320 and the flexible lower drive band 7330 and traverses through thearticulation joint area generally designated as 7200. The flexiblerotary drive shaft 7350 may be rotated by a motor/gear arrangementsupported in a housing of a surgical instrument. As the flexible rotarydrive shaft 7350 rotates in a first direction, the flexible upper driveband 7320 and the flexible lower drive band 7330 will drive the firingmember 7310 distally. Rotation of the flexible rotary drive shaft 7350in a second direction will cause the flexible upper drive band 7320 andthe flexible lower drive band 7330 to pull the firing member 7310proximally. In at least one arrangement, flexible upper drive band 7320and the flexible lower drive band 7330 pass through a guide member 7360that surrounds the rotary drive nut 7340 to prevent the flexible upperdrive band 7320 and the flexible lower drive band 7330 from bypassingthe rotary drive nut 7340 during actuation of the flexible rotary driveshaft 7350. See FIG. 84.

In the illustrated arrangement, the firing member 7310 is configured tomove through the surgical end effector 7000 that comprises a first jaw7010 and a second jaw 7030 that is configured to move relative to thefirst jaw 7010. In one embodiment, the first jaw 7010 comprises anelongate channel 7012 that is configured to operably support a surgicalstaple cartridge therein. See FIGS. 80 and 81. The second jaw 7030comprises an anvil 7032 that is pivotally supported on the elongatechannel 7012 and is movable between an open position and a closedposition relative to the elongate channel 7012. As can be seen in FIG.82, in at least one form, the firing member 7310 comprises a shape thatis commonly referred to as an “E-beam”. The firing member 7310 comprisesa vertically extending firing member body 7312 that has a lower footfeature 7314 that comprises two laterally extending tabs 7315 that areconfigured to be slidably engage the elongate channel 7012 as the firingmember is driven axially therein. In addition, a pair of upper tabs 7316protrude from the upper portion of the firing member body 7312 to engagethe anvil 7032 as the firing member 7310 is driven distally through theclosed anvil 7032. During the firing stroke, the tabs 7315 and 7316 mayserve to space the anvil 7032 relative to the surgical staple cartridgesupported in the elongate channel 7012. The firing member body 7312 alsocomprises a tissue cutting feature 7318. The tabs 7316 may also serve toapply a closing motion to the anvil 7032 as the firing member 7310 ismoved distally from the starting position.

In the illustrated example, the firing drive system 7300 may also beemployed to apply opening and closing motions to the anvil 7032. As canbe seen in FIGS. 80-83, a closure nut 7370 is threadably received on theflexible rotary drive shaft 7350. The closure nut 7370 comprises a campin 7372 that extends laterally from each side of the closure nut 7370to be received in corresponding cam slots 7036 in an anvil mountingportion 7034 of the anvil 7032. See FIGS. 80 and 81. Such cam pins 7372prevent the closure nut 7370 from rotating with the flexible rotarydrive shaft 7350 such that rotation of the flexible rotary drive shaft7350 causes the closure nut 7370 to move axially. Thus, rotation of theflexible rotary drive shaft 7350 in a first direction causes the closurenut 7370 to move distally and cam the anvil 7032 from the open positionto the closed position. Rotation of the flexible rotary drive shaft 7350in the second rotary direction will cause the closure nut 7370 to moveproximally and cam the anvil 7032 back to the open position. Thus,alternating the rotation of the flexible rotary drive shaft 7350 mayallow the surgeon to quickly open and close the anvil 7032 for graspingpurposes, for example.

FIG. 85 illustrates an alternative firing drive assembly 7302 thatcomprises the flexible upper drive band 7320′ that has upper drive teeth7322′ and a flexible lower drive band 7330′ that has lower drive teeth7332′ that is formed out of one piece of material such as metal. Theflexible upper drive band 7320′ also includes upper strength tabs 7324′that are provided to pass through the anvil 7032 similar to the uppertabs 7316 on the firing member 7310 as well as lower strength tabs 7334that are provided to pass through the channel 7012 similar to the tabs7315 on the firing member 7310. FIG. 86 illustrates an alternativefiring drive assembly 7302′ that is fabricated from two band assemblies7302A and 7302B that are laminated together to form the flexible upperdrive band 7320″ that has the upper drive teeth 7322″ and a flexiblelower drive band 7330″ that has the lower drive teeth 7332″. Each bandassembly 7302A, 7302B also comprise upper strength tabs 7324A″, 7324B″and lower strength tabs 7334A″, 7334B″ that are provided to pass throughthe anvil 7032 and the elongate channel 7012, respectively.

The firing drive system 7300 serves to apply a uniform drive motion tothe firing member 7310 and can accommodate articulation angles that maybe greater than seventy degrees, for example. In addition, because therotary drive nut 7340 engages the flexible upper drive band 7320 andflexible lower drive band 7330 at a location that is distal to thearticulation joint area 7200, the linear firing loads are confined tothe end effector and do not go through the articulation joint.

FIGS. 87-89 illustrate another form of surgical instrument 9010 that mayaddress many of the challenges facing surgical instruments with endeffectors that are articulatable to large articulation angles and thatare configured to cut and fasten tissue. In various embodiments, thesurgical instrument 9010 may comprise a handheld device. In otherembodiments, the surgical instrument 9010 may comprise an automatedsystem sometimes referred to as a robotically-controlled system, forexample. In various forms, the surgical instrument 9010 comprises asurgical end effector 10000 that is operably coupled to an elongateshaft assembly 12000. The elongate shaft assembly 12000 may be operablyattached to a housing. In one embodiment, the housing may comprise ahandle that is configured to be grasped, manipulated and actuated by theclinician. In other embodiments, the housing may comprise a portion of arobotic system that houses or otherwise operably supports at least onedrive system that is configured to generate and apply at least onecontrol motion which could be used to actuate the surgical end effectorsdisclosed herein and their respective equivalents. In addition, variouscomponents may be “housed” or contained in the housing or variouscomponents may be “associated with” a housing. In such instances, thecomponents may not be contained with the housing or supported directlyby the housing. For example, the surgical instruments disclosed hereinmay be employed with various robotic systems, instruments, componentsand methods disclosed in U.S. Pat. No. 9,072,535, entitled SURGICALSTAPLING INSTRUMENTS WITH ROTATABLE STAPLE DEPLOYMENT ARRANGEMENTS,which is incorporated by reference herein in its entirety.

In one form, the surgical end effector 10000 comprises a first jaw 10100and a second jaw 10200. In the illustrated arrangement, the first jaw10100 comprises an elongate channel 10110 that comprises a proximal end10112 and a distal end 10114 and is configured to operably support asurgical staple cartridge 10300 therein. The surgical staple cartridge10300 comprises a cartridge body 10302 that has an elongate slot 10304therein. A plurality of surgical staples or fasteners (not shown) arestored therein on drivers (not shown) that are arranged in rows on eachside of the elongate slot 10304. The drivers are each associated withcorresponding staple cavities 10308 that open through a cartridge decksurface 10306. The surgical staple cartridge 10300 may be replaced afterthe staples/fasteners have been discharged therefrom. Other embodimentsare contemplated wherein the elongate channel 10110 and/or the entiresurgical end effector 10000 is discarded after the surgical staplecartridge 10300 has been used.

In the illustrated arrangement, the second jaw 10200 comprises an anvil10210 that comprises an elongate anvil body 10212 that has a proximalend 10214 and a distal end 10216. The anvil body 10212 comprises astaple-forming undersurface 10218 that faces the first jaw 10100 and mayinclude a series of staple-forming pockets (not shown) that correspondto each of the staples or fasteners in the surgical staple cartridge10300. The anvil body 10212 may further include a pair of downwardlyextending tissue stop features 10220 that are formed adjacent theproximal end 10214 of the anvil body 10212. One tissue stop feature10220 extends from each side of the anvil body 10212 such that a distalend 10222 on each tissue stop 10220 corresponds to the proximal-moststaples/fasteners in the surgical staple cartridge 10300. When the anvil10200 is moved to a closed position onto tissue positioned between thestaple-forming undersurface 10218 of the anvil 10200 and the cartridgedeck surface 10306 of the surgical staple cartridge 10300, the tissuecontacts the distal ends 10222 of the tissue stops 10220 to prevent thetissue from migrating proximally past the proximal-moststaples/fasteners to thereby ensure that the tissue that is cut is alsostapled. When the surgical staple cartridge is “fired” as will bediscussed in further detail below, the staples/fasteners supportedwithin each staple cavity are driven out of the staple cavity 10308through the clamped tissue and into forming contact with the stapleforming undersurface 10218 of the anvil 10200.

As can be seen in FIG. 88, the proximal end 10214 of the anvil body10212 comprises an anvil mounting portion 10230 that comprises a pair oflaterally extending mounting pins 10232 that are configured to bereceived in corresponding mounting inserts 10130 that are configured tobe retainingly received within mounting cradles 10120 formed in theproximal end 10112 of the elongate channel 10110. The mounting pins10232 are pivotally received within pivot holes 10132 in the mountinginserts 10130 and then the mounting inserts 10130 are inserted intotheir corresponding cradle 10120 and affixed to the elongate channel10110 by welding, adhesive, snap fit, etc. Such arrangement facilitatespivotal travel of the anvil 10210 relative to the elongate channel 10110about a fixed (i.e., non-translating, non-moving) pivot axis PA. SeeFIG. 87.

In the illustrated arrangement, the elongate shaft assembly 12000defines a shaft axis SA and comprises a hollow outer tube (omitted forclarity) that operably interfaces with a housing of the control portion(e.g., handheld unit, robotic tool driver, etc.) of the surgicalinstrument 9010. The elongate shaft assembly 12000 further comprises anarticulation joint 12200 that may be attached to the hollow outer tubeas well as the surgical end effector 10000 to facilitate selectivearticulation of the surgical end effector 10000 relative to the elongateshaft assembly 12000 about multiple articulation axes in multiplearticulation planes. In at least one arrangement, for example, thearticulation joint 12200 comprises a proximal joint member 12210, acentral joint member 12230, and a distal joint member 12250. In oneexample, the central joint member 12230 operably interfaces with theproximal joint member 12210 such that the central joint member 12230 isselectively articulatable through a first or proximal articulation planethat is defined by a first or proximal articulation axis AA₁ that istransverse to the shaft axis SA. Also in one example, the distal jointmember 12250 operably interfaces with the central joint member 12230such that the distal joint member 12250 is selectively articulatablethrough a second or distal articulation plane that is defined by asecond or distal articulation axis AA₂ that is transverse to the shaftaxis SA and transverse to the first or proximal articulation axis AA₁.

As can be seen in FIGS. 89 and 90, the proximal joint member 12210comprises a proximal joint distal face 12212 that defines two spaced,lateral apex portions 12214, 12216. The apex portion 12214 defines aradial surface 12215 and the apex portion 12216 defines a radial surface12217 (FIG. 90). The central joint member 12230 comprises proximal face12232 that defines two spaced lateral proximal apex portions 12234,12236. The proximal apex portion 12234 defines a radial surface 12235and the apex portion 12236 defines a radial surface 12237. As can beseen in FIG. 89, the proximal face 12232 of the central joint member12230 confronts the proximal joint distal face 12212 of the proximaljoint member 12210 such that the central joint member 12230 isarticulatable through a first articulation plane defined by the first orproximal articulation axis AA₁ that extends between a point where thelateral apex portion 12214 on the proximal joint member contacts theproximal apex portion 12234 on the central joint member 12230 and thepoint where the lateral apex portion 12216 on the proximal joint member12210 contacts the proximal apex portion 12236 on the central jointmember 12230. In one arrangement, the radial surfaces 12215, 12217 onthe lateral apex portions 12214, 12216, respectively, and the radialsurfaces 12235 and 12237 on the proximal apex portions 12234, 12236,respectively, may act as rocker points/surfaces about which the centraljoint member 12230 may articulate relative to the proximal joint member12210. Additionally, the central joint member 12230 comprises proximalfirst gear tooth segments that are configured to rotatably mesh withdistal gear segments 12218, 12220 on the proximal joint member 12210.See FIG. 88. In various arrangements, the radial surface 12235 on thecentral joint member 12230 may be spaced from the radial surface 12215on the proximal joint member 12210 and the radial surface 12237 on thecentral joint member 12230 may be spaced from the radial surface 12217on the proximal joint member 12210.

The central joint member 12230 further comprises a central joint distalface 12240 that defines a centrally disposed upper apex portion 12242that forms an upper radial surface 12244 and a lower apex portion 12246that forms a lower radial surface 12248. See FIG. 89. The distal jointmember 12250 is attached to the proximal end 10112 of the elongatechannel 10110 by a mounting bushing 10150 and comprises a proximal face12251 that faces or confronts the central joint distal face 12240 on thecentral joint member 12230. See FIGS. 89 and 92. As can be seen in FIGS.89 and 92, the proximal face 12251 defines a centrally disposed upperapex portion 12252 that forms an upper radial surface 12254 that isconfigured to confront or abut the upper radial surface 12244 on thecentral joint member 12230. The proximal face 12251 further defines acentrally disposed lower apex portion 12256 that forms a lower radialsurface 12258 that is configured to confront or abut the lower radialsurface 12248 on the central joint member 12230. See FIG. 89. The distaljoint member 12250 further comprises an upper gear tooth segment 12253that is configured to rotatably mesh with an upper gear tooth segment12243 on the central joint member 12230. In addition, the distal jointmember 12250 comprises a lower gear tooth segment 12255 that isconfigured to rotatably mesh with a lower gear tooth segment 12245 onthe central joint member 12230. See FIG. 92.

The distal joint member 12250 is configured to articulate through asecond or distal articulation plane defined by the second or distalarticulation axis AA₂ that extends between a point where the upper apexportion 12252 on the distal joint member 12250 contacts or confronts theupper apex portion 12242 on the central joint member 12230 and the pointwhere the lower apex portion 12256 on the distal joint member 12250contacts or confronts the lower apex portion 12246 on the central jointmember 12230. See FIGS. 89 and 92. In one arrangement, the radialsurfaces 12254, 12258 on the upper and lower apex portions 12252, 12256,respectively of the distal joint member 12250 and the radial surfaces12244 and 12248 on the upper and lower apex portions 12242, 12246,respectively on the central joint member 12230 may act as rockerpoints/surfaces about which the distal joint member 12250 may articulaterelative to the central joint member 12230. In alternative arrangements,however, the radial surface 12254 on the distal joint member 12250 isspaced from the radial surface 12244 on the central joint member 12230and the radial surface 12258 on the distal joint member 12250 is spacedfrom the radial surface 12248 on the central joint member 12230.

Returning to FIG. 88, in the illustrated example, the articulation joint12200 is operably controlled by a cable control system 9030 thatcomprises four cables 12510, 12520, 12530, and 12540 that extend throughthe elongate shaft assembly 12000. The cable control system 9030 may besupported within a housing 9020 of the surgical instrument 9010. Thecable control system 9030 may comprise a plurality of cable supportmembers/capstans, pulleys, etc. that are controlled by one or morecorresponding motors that are controlled by a control circuit portion ofthe surgical instrument 9010. In various embodiments, the cable controlsystem 9030 is configured to manage the tensioning (pulling) and payingout of cables at precise times during the articulation process. Inaddition, in at least one arrangement, the cable control system 9030 isemployed to control the opening and closing of the anvil 10210 as willbe discussed in further detail below.

As can be seen in FIG. 88, the cables 12510, 12520, 12530, and 12540 areconfigured to operably interface with a closure system 12600 that isrotatably mounted in the proximal end 10112 of the elongate channel10110. In at least one arrangement, the closure system 12600 comprises apulley unit 12610 that comprises a first lateral alpha wrap pulley 12620and a second lateral alpha wrap pulley 12630 that are interconnected bya central shaft 12640. See FIGS. 93 and 94. The pulley unit 12610 isrotatably supported within the proximal end 10112 of the elongatechannel 10110 by mounting brackets 12710 and 12720. See FIG. 88. Moreparticularly, the proximal end 10112 of the elongate channel 10110defines a firing member parking area 10140 that is proximal to themounting cradles 10120 and is configured to operably support a firingmember 12310 when in a starting position. Each mounting bracket 12710,12720 is mounted within the firing member parking area 10140 on eachside of the shaft axis SA to enable the firing member 12310 to bereceived in the parking area 10140 when the firing member 12310 is in astarting position. The mounting brackets 12710, 12720 may be attached tothe proximal end 10112 of the elongate channel 10110 by welding,adhesive, snap features, etc. The mounting bracket 12710 comprises afirst shaft cradle 12712 that is configured to rotatably support a firstpivot shaft 12621 protruding from the first lateral alpha wrap pulley12620 and the second mounting bracket 12720 comprises a second shaftcradle 12722 that is configured to rotatably support a second pivotshaft 12644 protruding from the second lateral alpha wrap pulley 12630.In addition, each mounting bracket 12710, 12720 further includes arelief area 12732 that is shaped to receive the corresponding first andsecond alpha wrap pulleys 12620, 12630 therein.

As can be seen in FIG. 94, the first alpha wrap pulley 12620 comprises afirst circumferential groove 12622 and a second circumferential groove12624. In the illustrated example, the first cable 12510 is received inthe first circumferential groove 12622 and is attached thereto and thesecond cable 12520 is received in the second circumferential groove12624 and is attached thereto. Pulling on the first cable 12510 willresult in the rotation of the first lateral alpha wrap pulley 12620 in afirst direction and pulling the second cable 12520 will result in therotation of the first lateral alpha wrap pulley 12620 in a secondopposite direction. Similarly, the second lateral alpha wrap pulley12630 comprises a first circumferential groove 12632 and a secondcircumferential groove 12634. In the illustrated arrangement, cable12540 is received in the first circumferential groove 12632 and isattached thereto and the second cable 12520 is received in the secondcircumferential groove 12634 and is attached thereto. Pulling on thefourth cable 12540 will result in the rotation of the first second alphawrap pulley 12630 in the first direction and pulling the third cable12530 will result in the rotation of the second lateral alpha wrappulley 12630 in the second opposite direction. The lateral alpha wrappulleys 12620, 12630 can rotate approximately three hundred thirtydegrees. This range of rotational travel is in contrast to a normalpulley that may have a range of rotational travel that is less than onehundred eighty degrees of rotation.

Each of the first and second lateral alpha wrap pulleys 12620, 12630also comprises a corresponding spiral closure cam that is configured toapply closure motions to the anvil 10210. As can be seen in FIG. 94, thefirst lateral alpha wrap pulley 12620 includes a first spiral closurecam 12626 and the second lateral alpha wrap pulley 12630 has a secondspiral closure cam 12636 thereon. The spiral closure cams 12626, 12636are configured to cammingly interact with corresponding anvil closurearms 10234 on the anvil mounting portion 10230 of the anvil 10210 toapply closure motions thereto. FIG. 96 illustrates the position of aspiral closure cam 12626 on the first lateral alpha wrap pulley 12620when the anvil 10210 is biased into the open position by an anvil spring10240. Rotation of the pulley unit 12610 in a first rotary directionwill cause the spiral closure cams 12626 to cam the anvil 1210 to theclosed position shown in FIG. 97. To open the anvil 10210, the pulleyunit 12610 is rotated in opposite direction back to the position shownin FIG. 96.

Referring now to FIGS. 91 and 93, the first cable 12510 extends from thecable control system through the elongate shaft assembly and through apassage in the proximal joint member 12210 and is looped around tworedirect pulleys 12650, 12660 that are supported on shafts 12602, 12612that are mounted in the central joint member 12230. The first cable12510 exits the central joint member 12230 through passage 12231 andextends through passage 12257 in the distal joint member 12250 to bereceived within the first circumferential groove 12622 in the firstlateral alpha wrap pulley 12620 where it is attached thereto. A secondcable 12520 extends from the cable control system through the elongateshaft assembly and through passage 12213 in the proximal joint member12210 to be looped around the redirect pulleys 12650, 12660 in thecentral joint member 12230. The second cable 12520 exits the centraljoint member 12230 through a corresponding passage 12241 and extendsthrough passage 12259 in the distal joint member 12250 to be receivedwithin the second circumferential groove 12624 in the first lateralalpha wrap pulley 12620 where it is attached thereto.

In the illustrated example, the third cable 12530 extends from the cablecontrol system 9030 through the elongate shaft assembly 12000 andthrough a corresponding passages in the proximal joint member 12210, thecentral joint member 12230, and the distal joint member 12250 to bereceived within a corresponding circumferential groove in the secondlateral alpha wrap pulley 12630 where it is attached thereto. Inaddition, a fourth cable 12540 extends from the cable control system9030 through the elongate shaft assembly 12000 and through correspondingpassages in the proximal joint member 12210, the central joint member12230, and the distal joint member 12250 to be received within acorresponding circumferential groove in the second lateral alpha wrappulley 12630 where it is attached thereto.

In at least one example, to articulate the surgical end effector 10000relative to the elongate shaft assembly 12000 through a firstarticulation plane that is defined by the first articulation axis AA₁,the cable control system 9030 is actuated to pull on the second cable12520 and the fourth cable 12540 simultaneously with a same amount oftension being applied to each cable 12520 and 12540. Because the cables12520, 12540 apply equal amounts of tension on both sides of the pulleyunit 12610, the pulley unit 12610 does not rotate. However, the pullingaction of the cables 12520 and 12540 is translated through thearticulation joint 12200 to the surgical end effector 10000 whichresults in the articulation of the central joint member 12230 relativeto the proximal joint member 12210 about the first articulation axisAA₁. See FIGS. 92 and 98. To articulate the surgical end effector 10000through a second plane of articulation that is defined by the secondarticulation axis AA₂ and is transverse to the first plane ofarticulation, the cable control system 9030 is actuated to pull thethird cable 12530 and the fourth cable 12540 simultaneously with a sameamount of tension being applied to each cable 12530 and 12540. Becausethe cables 12530, 12540 apply equal amounts of tension on both sides ofthe second lateral alpha wrap pulley 12630 of the pulley unit 12610, thepulley unit 12610 does not rotate. However, the pulling action of thecables 12530 and 12540 is translated through the articulation joint12200 to the surgical end effector 10000 which results in thearticulation of the distal joint member 12250 relative to the centraljoint member 12230 about the second articulation axis AA₂. See FIGS. 92and 99.

The cable control system 9030 may also be used to control the openingand closing of the anvil 10210 in the following manner. As indicatedabove, when the spiral cams 10626 on the first lateral alpha wrap pulley10620 and the second lateral alpha wrap pulley 10630 are in the positionshown in FIG. 96, the anvil 10210 is biased into the open position bythe anvil spring 10240. To close the anvil 10210 from that position, thecable control system 9030 is actuated to pull the first cable 12510 andthe fourth cable 12540 simultaneously with a same amount of tensionbeing applied to each cable 12510 and 12540. These cables 12510 and12540 will cause the pulley unit 12610 to rotate into the closureposition shown in FIG. 97 which causes the closure cams 10626 tocammingly contact the anvil closure arms 10234 to pivot the anvil 10210into the closed position. It will be appreciated that by applying equalamounts of tension into the cables 12510 and 12540, no moment is appliedto the central joint member 12230 and/or distal joint member 12250because there are equal amounts of tension being applied on each side ofthe articulation joint 12200. See FIG. 91. Such arrangement allows thejaw closure to be profiled as desired. This cable-controlled system 9030allows for a faster closure when the anvil is fully open. Thecable-controlled system 9030 can also function as a lower speed/higherforce generating closure mechanism for clamping onto tissue. The presentcable controlled system 9030 may also not produce the backlash thatcommonly occurs with other cable-controlled systems and thus can also beused to control the articulation position of the end effector. As willbe further discussed below, this cable actuated closure and articulationsystem does not cross across the center axis or shaft axis of thearticulation joint which provides critical space for a firing drivesystem 13000.

The above-described articulation joint 12200 and cable controlled system9030 can facilitate two plane articulation while also supplying anadditional actuation motion to the surgical end effector 10000 whilekeeping the central area of the articulation joint 12200 free for othercontrol systems as will be discussed in further detail below. Thearticulation joint 12200 uses the last degree of freedom to actuate thejaw closure of the surgical end effector. In one aspect, thearticulation joint 12200 comprises an N+1 joint, meaning that for Ndegrees of freedom, the joint requires N+1 cables to actuate it. Thus,in the above-described example, the articulation joint 12200 employsfour actuation cables.

As can be seen in FIGS. 100-103, the firing drive system 13000 comprisesa firing member 13310 that includes a vertically-extending firing memberbody 13312 that has two laterally extending tabs 13314 protruding from abottom portion 13313 of the firing member body 13312. The tabs 13314 areconfigured to be slidably engage ledges 10113 in the elongate channel10110 as the firing member 13310 is driven axially therein. In addition,a pair of upper tabs 13316 protrudes from a top portion 13315 of thefiring member body 13312. The upper tabs 13316 are configured to engageledges 10213 (FIG. 103) in the anvil body 10212 as the firing member13310 is driven distally through the closed anvil 10210. During thefiring stroke, the tabs 13314 and 13316 may serve to space the anvil10210 relative to a surgical staple cartridge that is supported in theelongate channel 10110. The firing member body 13312 also comprises atissue cutting feature 13318 and a proximally-facing notch 13319 that isconfigured to accommodate the central shaft 12640 of the pulley unit12610 when the firing member 13310 is in its proximal-most startingposition within the firing member parking area 10140 in the proximal end10112 of the elongate channel 10110.

As shown in FIGS. 100-102, the firing drive system 13000 furthercomprises an upper flexible chain drive assembly 13400 that is operablycoupled to the top portion 13315 of the firing member 13310 and a lowerflexible chain drive assembly 13500 that is operably coupled to thebottom portion 13313 of the firing member 13310. In at least oneembodiment, the upper flexible chain drive assembly 13400 comprises anupper series 13410 of upper chain link features 13420 that are looselycoupled together by an upper flexible coupler member 13402 that isattached to the top portion 13315 of the firing member 13310. In atleast one example, each upper chain link feature 13420 comprises anupper ball or sphere 13422 that has an upper hollow passage 13424therein that is configured to permit the upper flexible coupler member13402 to pass therethrough. As can be seen in FIG. 100, the upperflexible chain drive assembly 13400 further comprises an uppercompression assembly 13430 for compressing the upper balls 13422 in theupper series 13410 together. In one arrangement, the upper compressionassembly 13430 comprises a hollow flexible compression tube 13432 thatis received on the upper flexible coupler member 13402. An upper ferrule13440 is crimped onto the upper flexible coupler member 13402 and anupper compression spring 13442 is journaled between the upper ferrule13440 and the upper flexible compression tube 13432 to distally bias theupper flexible compression tube 13432 into contact with theproximal-most upper ball 13422P in the upper series 13410 of upper chainlink features 13420.

Similarly, in at least one embodiment, the lower flexible chain driveassembly 13500 comprises a lower series 13510 of lower chain linkfeatures 13520 that are loosely coupled together by a lower flexiblecoupler member 13502 that is attached to the bottom portion 13313 of thefiring member 13310. In at least one example, each lower chain linkfeature 13520 comprises a lower ball or sphere 13522 that has a lowerhollow passage 13524 therein that is configured to permit the lowerflexible coupler member 13502 to pass therethrough. The lower flexiblechain drive assembly 13500 further comprises an upper compressionassembly 13530 for compressing the lower balls 13522 in the lower series13510 together. In one arrangement, the lower compression assembly 13530comprises a hollow flexible compression tube 13532 that is received onthe lower flexible coupler member 13502. A lower ferrule 13540 iscrimped onto the lower flexible coupler member 13502 and a lowercompression spring 13542 is journaled between the lower ferrule 13540and the lower flexible compression tube 13532 to distally bias the lowerflexible compression tube 13532 into contact with the proximal-mostlower ball 13522P in the lower series 13510 of lower chain link features13520.

Now turning to FIG. 104, in at least one arrangement, the firing drivesystem 13000 further comprises rotary drive screw 13700 that isconfigured to drivingly interface with the upper series 13410 of upperchain link features 13420 and the lower series 13510 of lower chain linkfeatures 13520. As can be seen in FIG. 104, in the illustratedarrangement, the rotary drive screw 13700 is rotatably supported in themounting bushing 10150 that is attached to the proximal end 10112 of theelongate channel 10110. For example, the rotary drive screw 13700comprises a body portion 13702 that has a central axle 13704 protrudingtherefrom that is rotatably mounted in a mounting hole 10152 in themounting bushing 10150. Such arrangement permits the rotary drive screw13700 to rotate about the shaft axis SA.

In the illustrated example, the rotary drive screw 13700 is driven by arotary drive system 13600 that comprises a proximal rotary drive shaft13610 that is rotatably supported within an axial passage 12225 withinthe proximal joint member 12210. As can be seen in FIG. 105, theproximal rotary drive shaft 13610 comprises a proximal end 13612 and adistal end 13614. The proximal end 13612 may interface with a gearbox/motor arrangement 9050 or other source of rotary motion housed inthe housing 9020 of the surgical instrument 9010. Such source of rotarymotion causes the proximal rotary drive shaft 13610 to rotate about theshaft axis SA within the axial passage 12225 in the proximal jointmember 12210. See FIG. 104. As can be seen in FIG. 105, the distal end13614 of the proximal rotary drive shaft 13610 is movably coupled to afirst drive shaft segment 13620. In the illustrated example, the firstdrive shaft segment 13620 resembles a “dog bone” with a first sphericalproximal end 13622 and a first spherical distal end 13624. See FIG. 106.The first spherical proximal end 13622 is movably pinned within a firstdistal socket 13616 formed in the distal end 13614 of the proximalrotary drive shaft 13610 by a first proximal pin 13618. The firstproximal pin 13618 extends through an arcuate transverse slot 13623 inthe first spherical proximal end 13622. Such arrangement permits thefirst spherical proximal end 13622 to move in multiple directions withinthe first distal socket 13616 while remaining attached thereto. Thefirst spherical distal end 13624 is received within a first proximalsocket 13632 in a central bearing housing 13630 that is mounted withinthe central joint member 12230. The first spherical distal end 13624 ismovably pinned within the first proximal socket 13632 by a first distalpin 13634. The first distal pin 13634 extends through an arcuatetransverse slot 13625 in the first spherical distal end 13624. Sucharrangement permits the first spherical distal end 13624 to move inmultiple directions within the first proximal socket 13632 whileremaining attached to the central bearing housing 13630.

As can be seen in FIG. 105, the rotary drive system 13600 furthercomprises a second drive shaft segment 13640 that resembles the firstdrive shaft segment 13620 and includes a second spherical proximal end13642 and a second spherical distal end 13644. The second sphericalproximal end 13642 is movably pinned within a second distal socket 13636that is formed in the central bearing housing 13630 by a second proximalpin 13637. The second proximal pin 13637 extends through an arcuatetransverse slot 13643 in the second spherical proximal end 13642. Sucharrangement permits the second spherical proximal end 13642 to move inmultiple directions within the second distal socket 13636 whileremaining attached thereto. The second spherical distal end 13644 isreceived within a second proximal socket 13706 in the rotary drive screw13700 and is movably pinned within the second proximal socket 13706 by asecond distal pin 13647. The second distal pin 13647 extends through atransverse slot 13646 in the second spherical distal end 13644. Sucharrangement permits the second spherical distal end 13644 to move inmultiple directions relative to the rotary drive screw 13700.

The double joint rotary drive maintains a linear velocity output byusing the angle constraint of the joint members of the articulationjoint. This universal rotary joint arrangement on its own may have asinusoidal output based on the angle of the joint. If the angles areequal and the phases are aligned correctly, the sine output of the firstuniversal joint will be canceled out by the second universal joint,producing a linear rotational velocity. This is an advantage to puttinga constraint in the rotary drive because it decreases the complexity ofthe components and prevents the need to remove material from thecomponents to attain the requisite clearance. Thus, the components ofthis embodiment are more robust and stronger than prior arrangements.Further, the constant velocity of the rotary drive system will allow forsmoother firing and reduced wear that may be otherwise caused byvibration.

Returning to FIG. 102, the rotary drive screw 13700 comprises helicalgrooves or drive features 13708 formed on a circumference thereof thatare configured to engage and drive the upper balls or spheres 13422 inthe upper series 13410 of upper chain link features 13420 and the lowerballs or spheres 13522 in the lower series 13510 of lower chain linkfeatures 13520. Thus, to drive the firing member 13310 from a startingposition in the surgical end effector 10000 to an ending position withinthe end effector, the rotary drive system 13600 is actuated to apply arotary drive motion to the rotary drive screw 13700. As the rotary drivescrew 13700 rotates in the first rotary direction, the helical drivefeatures 13708 engage the upper balls or spheres 13422 in the upperseries 13410 of upper chain link features 13420 and the lower balls orspheres 13522 in the lower series 13510 of lower chain link features13520 and drive the upper flexible chain drive assembly 13400 and thelower flexible chain drive assembly 13500 distally. As each upper ball13422 and lower ball 13522 engage the rotary drive screw 13700, theupper balls 13422 in the upper series 13410 that are distal to therotary drive screw 13700 (and the articulation joint 12200) and thelower balls 13522 in the lower series 13510 that are distal to therotary drive screw 13700 (and the articulation joint 12200) are placedunder compression to apply balanced axial drive forces to the firingmember 13310. When the upper flexible chain drive assembly 13400 and theflexible lower chain drive assembly 13500 are in compression, they areconstrained by the slots in the anvil 10210 and the elongate channel10110, respectively. Such arrangement ensures that, when the upperflexible chain drive assembly 13400 and lower flexible chain driveassembly 13500 are compressed, they do not buckle.

This arrangement enables two degrees of articulation freedom for a fewreasons. For example, the upper flexible chain drive assembly 13400 andlower flexible chain drive assembly 13500 can bend freely both in thepitch and yaw axes. Thus, the upper flexible chain drive assembly 13400and lower flexible chain drive assembly 13500 can assume a variety ofconfigurations that can accommodate various articulated positions thatare attainable with the articulation joint 12200. Once the firing member13310 has traveled through the surgical end effector 10000 distally toan ending position therein, the rotary drive system 13600 is actuated toapply a second rotary drive motion to the rotary drive screw 13700 tocause the rotary drive screw 13700 to rotate about the shaft axis in asecond rotary direction. As the rotary drive screw 13700 rotates in thesecond rotary direction, the upper flexible chain drive assembly 13400and the lower flexible chain drive assembly 13500 serve to retract thefiring member 13310 in the proximal direction back to the startingposition. As the upper flexible chain drive assembly 13400 and the lowerflexible chain drive assembly 13500 retract the firing member 13310proximally, a portion of the upper flexible chain drive assembly 13400and the lower flexible chain drive assembly 13500 traverse back throughthe articulation joint 12200 and into the elongate shaft. Sucharrangement allows the firing member 13310 to translate a long distance,without increasing the length of the end effector joint. Additionally,because the rotary drive screw 13700 drivingly engages the upperflexible chain drive assembly 13400 and the lower flexible chain driveassembly 13500 at a location that is distal to the articulation joint12200, the high compressive loads are contained within the surgical endeffector 10000 and do not create a moment on the articulation joint12200. This arrangement may greatly reduce the strength requirements ofthe articulation joint. See FIG. 104.

In at least one arrangement, the surgical instrument 9010 may furthercomprise a cable tensioning system 13800 that is configured to maintaina desired amount of tension on the upper flexible chain drive assembly13400 and the lower flexible chain drive assembly 13500 as they bendthrough the articulation joint 12200. Keeping the upper flexible chaindrive assembly 13400 and the lower flexible chain drive assembly 13500under a desired amount of tension as they traverse through thearticulation joint 12200 may prevent slack from forming in thoseflexible chain drive assemblies 13400, 13500 which might otherwise causethem to undesirably bunch up in the articulation joint 12200. FIGS. 111and 112 illustrate one form of cable tensioning system 13800 whichcomprises constant force spring arrangements 13810 and 13820. Suchsolution has the benefit of not requiring length conservation of theflexible chain drive assemblies 13400, 13500.

Another cable management system 13800′ is illustrated in FIGS. 113 and114. In this arrangement, the proximal ends of the flexible chain driveassemblies 13400, 13500 are coupled together and journaled around acable management pulley 13840 that is configured to translate with thefiring member 13310. When the firing member 13310 is distally advancedduring the firing stroke, the cable management pulley 13840 alsotranslates distally maintaining tension in the flexible chain driveassemblies 13400, 13500. During articulation, a length of one of theflexible chain drive assemblies 13400, 13500 would increase, while theother would decrease. Such arrangement serves to minimize the lengths ofthe flexible chain drive assemblies 13400, 13500 required to fullyactuate and articulate the surgical end effector 10000.

One method of using the surgical instrument 9010 may involve the use ofthe surgical instrument to cut and staple target tissue within a patientusing laparoscopic techniques. For example, one or more trocars may havebeen placed through the abdominal wall of a patient to provide access toa target tissue within the patient. The surgical end effector 10000 maybe inserted through one trocar and one or more cameras or other surgicalinstruments may be inserted through the other trocar(s). To enable thesurgical end effector 10000 to pass through the trocar cannula, thesurgical end effector 10000 is positioned in an unarticulatedorientation (FIG. 63) and the jaws 10100 and 10200 must be closed. Toretain the jaws 10100 in the closed position for insertion purposes, forexample, the cable control system 9030 is actuated to pull the firstcable 12510 and the fourth cable 12540 simultaneously which causes thepulley unit 12610 to rotate and cause the closure cams 10626, 10636 tocontact the anvil closure arms 10234 to pivot the anvil 10210 into theclosed position. See FIG. 97. The cable control system 9030 isdeactivated to retain the anvil 10210 in the closed position. Once thesurgical end effector 10000 has passed into the abdomen through thetrocar, the cable control system 9030 is activated to rotate the pulleyunit 12610 in an opposite direction to the position shown in FIG. 96 topermit the anvil 10210 to be biased open by the anvil springs 10240.

Once inside the abdomen and before engaging the target tissue, thesurgeon may need to articulate the surgical end effector 10000 into anadvantageous position. The cable control system 9030 may then beactuated to articulate the surgical end effector 10000 in one or moreplanes relative to a portion of the elongate shaft assembly 12000 thatis received within the cannula of the trocar. Once the surgeon hasoriented the surgical end effector 10000 in a desirable position, thecable control system 9030 is deactivated to retain the surgical endeffector 10000 in the articulated orientation. Thereafter, the surgeonmay activate the cable control system 9030 in the above-described mannerto cause the anvil 10210 to rapidly close to grasp the tissue betweenthe anvil 10210 and the surgical staple cartridge 10300. This processmay be repeated as necessary until the target tissue has be properlypositioned between the anvil 10210 and the surgical staple cartridge10300.

Once the target tissue has been positioned between the anvil 10210 andthe surgical staple cartridge 10300, the surgeon may activate the cablecontrol system 9030 to close the anvil 10210 to clamp the target tissuein position. Thereafter, the firing process may be commenced byactivating the rotary drive system 13600 to drive the firing member13310 distally from the starting position. As the firing member 13310moves distally, the firing member 13310 contacts a sled that issupported in the surgical staple cartridge 10300 and also drives thesled distally through the staple cartridge body. The sled seriallydrives rows of drivers supported in the staple cartridge toward theclamped target tissue. Each driver has supported thereon one or moresurgical staples or fasteners which are then driven through the targettissue and into forming contact with the underside of the anvil 10210.As the firing member 13310 moves distally, the tissue cutting edge 13318thereon cuts through the stapled tissue.

After the firing member 13310 has been driven distally to the endingposition within the surgical end effector 10000, the rotary drive system13600 is reversed which causes the firing member 13310 to retractproximally back to the starting position. Once the firing member 13310has returned to the starting position, the cable control system 9030 maybe activated to rotate the pulley unit 12610 back to an open positionwherein the anvil springs 10240 can pivot the anvil 10210 to the openposition to enable the surgeon to release the stapled tissue from thesurgical end effector 10000. Once the stapled tissue has been released,the surgical end effector 10000 may be withdrawn out of the patientthrough the trocar cannula. To do so, the surgeon must first actuate thecable control system 9030 to return the surgical end effector 10000 toan unarticulated position and actuate the cable control system 9030 topivot the anvil 10210 to the closed position. Thereafter, the surgicalend effector 10000 may be withdrawn through the trocar cannula.

In previous endocutter arrangements, the firing member is pushed by aflexible beam. In such arrangements, the articulation joint mustredirect the linear motion of the flexible beam as it enters thearticulation joint back to that linear motion as it exits thearticulation joint and enters the end effector. Because of the highloads required to push the flexible beam and the firing member, theflexible beam commonly experiences high amounts of friction as it exitsthe articulation joint and is linearly redirected into the end effector.This added amount of friction increases the amount of driving forcesthat are required to drive the firing member from the starting to endingposition within the end effector while the end effector is articulated.Further, as the flexible beam traverses the articulation joint, it mayapply de-articulation motions to the articulation joint components.Thus, the articulation joint components must be sufficiently robust soas to resist such de-articulation motions.

Other forms of surgical endocutters employ rotary forces to drive thefiring member through the end effector. Such arrangements commonlyemploy a rotary drive screw that is housed within the channel thatsupports the staple cartridge. During use, the sled and tissue placelarge moments on the firing member which decrease the efficiency of thesystem and ultimately require higher rotary forces to actuate the firingmember. It is difficult to move the rotary drive screw closer to thecenter of such forces because of the cartridge and the location of thetissue. It is also difficult to package a screw on top and bottom of thefiring member without increasing the overall diameter of the surgicalend effector. The various embodiments discussed above may address manyif not all of these issues and challenges.

FIGS. 115-139 illustrate another form of surgical instrument 25010 thatmay address many of the challenges facing surgical instruments thatcomprise end effectors that are articulatable to large articulationangles and that are configured to cut and fasten tissue. In variousembodiments, the surgical instrument 25010 may comprise a handhelddevice. In other embodiments, the surgical instrument 25010 maycomprises an automated system sometimes referred to as arobotically-controlled system, for example. In various forms, thesurgical instrument 25010 comprises a surgical end effector 26000 thatis operably coupled to an elongate shaft assembly 28000. The elongateshaft assembly 28000 may be operable attached to a housing. In oneembodiment, the housing may comprise a handle that is configured to begrasped, manipulated and actuated by the clinician. In otherembodiments, the housing may comprise a portion of a robotic system thathouses or otherwise operably supports at least one drive system that isconfigured to generate and apply at least one control motion which couldbe used to actuate the surgical end effectors disclosed herein and theirrespective equivalents. In addition, various components may be “housed”or contained in the housing or various components may be “associatedwith” a housing. In such instances, the components may not be containedwith the housing or supported directly by the housing. For example, thesurgical instruments disclosed herein may be employed with variousrobotic systems, instruments, components and methods disclosed in U.S.Pat. No. 9,072,535, entitled SURGICAL STAPLING INSTRUMENTS WITHROTATABLE STAPLE DEPLOYMENT ARRANGEMENTS, which is incorporated byreference herein in its entirety.

In one form, the surgical end effector 26000 comprises a first jaw 26100and a second jaw 26200. In the illustrated arrangement, the first jaw26100 comprises an elongate channel 26110 that comprises a proximal end26112 and a distal end 26114 and is configured to operably support asurgical staple cartridge 10300 therein. An example of a surgical staplecartridge 10300 was described in detail above. The second jaw 26200comprises an anvil 26210 that comprises an elongate anvil body 26212that has a proximal end 26214 and a distal end 26216. The anvil body26212 comprises a staple-forming undersurface 26218 that faces the firstjaw 26100 and may include a series of staple-forming pockets (not shown)that corresponds to each of the staples or fasteners in the surgicalstaple cartridge 10300. As can be seen in FIG. 119, the proximal end26214 of the anvil body 26212 comprises an anvil mounting portion 26230that comprises a pair of laterally extending mounting pins 26232 thatare configured to be received in corresponding mounting inserts 26130that are configured to be retainingly received within mounting cradles26120 formed in a proximal end 26112 of the elongate channel 26110. Themounting pins 26232 are pivotally received within pivot holes 26132 inthe mounting inserts 26130 and then the mounting inserts 26130 areinserted into their corresponding cradle 26120 and affixed to theelongate channel 26110 by welding, adhesive, snap fit, etc. Sucharrangement facilitates pivotal travel of the anvil 26210 relative tothe elongate channel 26110 about a fixed pivot axis PA. See FIG. 115. Asstated above, as used in this context, the term “fixed” means that thepivot axis PA is non-translating or non-moving relative to the elongatechannel 26110.

In the illustrated arrangement, the elongate shaft assembly 28000defines a shaft axis SA and comprises a shaft spine assembly 28100 thatis received in a hollow outer shaft tube 28102. See FIG. 119. The shaftspine assembly 28100 may operably interface with a housing of thecontrol portion (e.g., handheld unit, robotic tool driver, etc.) of thesurgical instrument 25010 and in one example, comprises a proximal spinesegment 28120 and a distal spine segment 28140.

The elongate shaft assembly 28000 further comprises an articulationjoint 28200 that may be attached to the distal spine segment 28140 aswell as the surgical end effector 26000 to facilitate selectivearticulation of the surgical end effector 26000 relative to the elongateshaft assembly 28000 in multiple articulation planes. Turning now toFIGS. 120-125, the articulation joint 28200 comprises a series 28202 ofmovably interfacing annular disc members 28210. As can be seen in FIGS.122, 123, and 125, each annular disc member 28210 comprises a “first” orproximal face 28220 that comprises a centrally-disposed sphericalfeature or protrusion 28222. Each annular disc member 28210 furthercomprises a second or distal face 28230 that comprises an annular hubportion 28232 that defines a concave socket 28234 therein. See FIGS. 122and 124. Each annular disc member 28210 further has a central shaftpassage 28236 therethrough. As can be seen in FIGS. 120 and 121, thearticulation joint 28200 further comprises a proximal attachment discassembly 28240 that is configured to be attached to a distal end of thedistal spine segment 28140 by welding, adhesive, or other suitablefastener arrangement. The proximal attachment disc assembly 28240comprises a distal face 28242 that includes an annular hub portion 28244that defines a concave socket 28246 therein. The proximal attachmentdisc 28240 further has a central shaft passage 28248 therethrough. Alsoin the illustrated arrangement, the anvil mounting bracket 26240 isconfigured to operably interface with the articulation joint 28200. Theanvil mounting bracket 26240 is attached to the proximal end 26112 ofthe elongate channel 26110 of the surgical end effector 26000 bywelding, adhesive or other suitable fastener arrangements and comprisesa proximal face 26244 that has a centrally-disposed spherical feature orprotrusion 26246 protruding therefrom. See FIG. 120. The anvil mountingbracket 26240 further has a central shaft passage 26248 therethrough.

In at least one embodiment, the articulation joint further comprises aseries 28270 of elastomeric annular spacer members 28280 that serve tospace and provide elastic support between each annular disc member28210. The elastomeric annular spacer members 28280 define a spaceropening 28282 such that each elastomeric spacer member 28280 may bejournaled on an annular hub portion 28232 of a corresponding annulardisc member 28210. Each annular disc member 28210 is journaled on acentral elastomeric support or continuum shaft 28300 that is mounted tothe proximal attachment disc assembly 28240 and the anvil mountingbracket 26240. In one arrangement, the central continuum shaft 28300 isfabricated from an elastomeric material (e.g., rubber, polymer, etc.)and comprises a flanged proximal end 28302 and a cylindrical bodyportion 28304. The cylindrical body portion 28304 comprises a series ofannular grooves 28306 therein. Each annular groove 28306 corresponds toone of the annular disc members 28210. The annular disc members 28210and annular spacer members 28280 are journaled on the central continuumshaft 28300 as shown in FIG. 120. The flanged proximal end 28302 of thecentral continuum shaft 28300 is supported in a proximal passage 28249in the proximal attachment disc 28240. The cylindrical body portion28304 of the central continuum shaft 28300 extends through the centralpassage 28236 in each of the annular disc members 28210 in the series28202 of movably interfacing annular disc members 28210. Eachcentrally-disposed spherical feature or protrusion 28222 comprises anannular key member 28224 that is configured to be received in acorresponding annular groove 28306 in the central continuum shaft 28300.Such arrangement may serve to orient each annular disc member 28210 in adesired spacing orientation on the central continuum shaft 28300, forexample.

Still referring to FIG. 120, a proximal-most elastomeric spacer member28280P is journaled on the annular hub portion 28244 of the proximalattachment disc assembly 28240 such that it is positioned between aproximal-most annular disc member 28210P and the proximal attachmentdisc 28240. The annular key member 28224 of the proximal-most annulardisc member 28210P is received within a corresponding annular groove28306 in the central continuum shaft 28300 to position thecentrally-disposed spherical feature or protrusion 28222 of theproximal-most annular disc member 28210P within the concave socket 28246in the annular hub portion 28244 of the proximal attachment disc 28240.As can further be seen in FIG. 120, another elastomeric spacer member28280A is journaled on the annular hub portion 28232 of theproximal-most annular disc member 28210P such that is positioned betweenthe next annular disc member 28210A in the series 28202 of movablyinterfacing annular disc members 28202 and the proximal-most annulardisc member 28210P. The annular key member 28224 of the annular discmember 28210A is received within a corresponding annular groove 28306 inthe central continuum shaft 28300 to position the centrally-disposedspherical feature or protrusion 28222 of the annular disc member 28210Awithin the concave socket 28246 in the annular hub portion 28244 of theproximal attachment disc 28210P. Still referring to FIG. 120, anotherelastomeric spacer member 28280B is journaled on the annular hub portion28232 of the annular disc member 28210A such that is positioned betweenthe next annular disc member 28210B in the series 28202 of movablyinterfacing annular disc members 28210. The annular key member 28224 ofthe annular disc member 28210B is received within a correspondingannular groove 28306 in the central continuum shaft 28300 to positionthe centrally-disposed spherical feature or protrusion 28222 of theannular disc member 28210B within the concave socket 28246 in theannular hub portion 28244 of the annular disc member 28210A. Also inthis arrangement, another elastomeric spacer member 28280C is journaledon the annular hub portion 28232 of the annular disc member 28210B suchthat is positioned between the distal-most annular disc member 28210C inthe series of movably interfacing annular disc members 28202. Theannular key member 28224 of the distal-most annular disc member 28210Cis received within a corresponding annular groove 28306 in the centralcontinuum shaft 28300 to position the centrally-disposed sphericalfeature or protrusion 28222 of the distal-most annular disc member28210C within the concave socket 28246 in the annular hub portion 28244of the annular disc member 28210B. Finally, another elastomeric spacermember 28280D is journaled on the annular hub portion 28232 of thedistal-most annular disc member 28210C such that is positioned betweenthe anvil mounting bracket 26240 and the distal-most annular disc member28210C. The annular key member 28224 of the centrally-disposed sphericalfeature or protrusion 26246 of the anvil mounting bracket 26240 isreceived within a corresponding annular groove 28306 in the centralcontinuum shaft 28300 to position the centrally-disposed sphericalfeature or protrusion 226246 of the anvil mounting bracket 26240 withinthe concave socket 28246 in the annular hub portion 28244 of thedistal-most annular disc member 28210C.

In at least one arrangement, to limit pivotal travel of the annular discmembers to a range of relative pivotal travel and prevent completerelative rotation of the annular disc members 28210 relative to eachother, the centrally-disposed spherical feature or protrusion 28222 ofeach of the annular disc member 28210P, 28210A, 28210B, 28210C, as wellas the distal spherical feature or protrusion 26246 of the anvilmounting bracket 26240, includes a pair of arcuate pin grooves 28226therein. As can be seen in FIG. 120, a corresponding travel-limiting pinmember 28227 is pressed into or otherwise attached to each annular hubportion 28232 and is received within the corresponding pin groove 28226in the centrally-disposed spherical feature or protrusions 28222, 26246.

Returning to FIG. 119, in the illustrated example, the articulationjoint 28200 may be operably controlled by an articulation system 28400that comprises four cable assemblies 28410, 28420, 28430, and 28440 thatextend through the elongate shaft assembly 28000. In one arrangement,the cable assembly 28410 comprises a proximal cable portion 28412 thatis attached to an articulation rod 28414 that is supported in acorresponding axial groove in the shaft spine assembly 28100 for axialtravel therein. A distal cable portion 28416 is attached to thearticulation rod 28414. The cable assembly 28420 comprises a proximalcable portion 28422 that is attached to an articulation rod 28424 thatis supported in a corresponding axial groove in the shaft spine assembly28100 for axial travel therein. A distal cable portion 28426 is attachedto the articulation rod 28414. The cable assembly 28430 comprises aproximal cable portion 28432 that is attached to an articulation rod28434 that is supported in a corresponding axial groove in the shaftspine assembly 28100 for axial travel therein. A distal cable portion28436 is attached to the articulation rod 28434. The cable assembly28440 comprises a proximal cable portion 28442 that is attached to anarticulation rod 28444 that is supported in a corresponding axial groovein the shaft spine assembly 28100 for axial travel therein. A distalcable portion 28446 is attached to the articulation rod 28444.

The proximal cable portions 28412, 28422, 28432, 28442 may operablyinterface with a portion of a cable control system 25030 that issupported within or is otherwise associated with a housing of thesurgical instrument 25010. The cable control system 25030 may comprise aplurality of cable support members/capstans, pulleys, etc. that arecontrolled by one or more corresponding motors that are controlled by acontrol circuit portion of the surgical instrument 25010. In variousembodiments, the cable control system 25030 is configured to manage thetensioning (pulling) and paying out of cables at precise times duringthe articulation process. In addition, in at least one arrangement, thecable control system 25030 may be employed to control the opening andclosing of the anvil 26210 as will be discussed in further detail below.

Turning now to FIG. 126, the distal cable portions 28416, 28426, 28436,28446 are configured to operably interface with a closure system 28500that is rotatably mounted in the proximal end 26112 of the elongatechannel 26110. As can be seen in FIG. 126, the closure system 28500comprises a pulley unit 28510 that comprises a first lateral alpha wrappulley 28520 and a second lateral alpha wrap pulley 28530 that areinterconnected by a central shaft 28540. The pulley unit 28510 isrotatably supported within the proximal end 26112 of the elongatechannel 26110 and retained therein by an anvil mounting bracket 26240that is attached to the proximal end 26112 of the elongate channel26112. See FIG. 119. The anvil mounting bracket 26240 may be attached tothe proximal end 26112 of the elongate channel 26110 by welding,adhesive, snap features, etc. The anvil mounting bracket 26240 comprisesa shaft cradle 26242 that is configured to rotatably support the centralshaft 28540 within the elongate channel 26110. In the illustratedarrangement, a first pivot shaft 28521 protrudes from the first lateralalpha wrap pulley 28520 and is pivotally supported in a pivot hole 26113in the proximal end of the elongate channel. Similarly, a second pivotshaft 28531 protrudes from the second lateral alpha wrap pulley 28530and is pivotally supported in a pivot hole 26115 in the proximal end26112 of the elongate channel 26110.

As can be seen in FIG. 126, the first alpha wrap pulley 28520 comprisesa first circumferential groove 28522 and a second circumferential groove28524. In the illustrated example, the first distal cable portion 28416is received in the first circumferential groove 28522 and is attachedthereto and the second distal cable portion 28426 is received in thesecond circumferential groove 28524 and is attached thereto. Pulling onthe first distal cable portion 28416 will result in the rotation of thefirst lateral alpha wrap pulley 28520 in a first direction and pullingthe second distal cable portion 28426 will result in the rotation of thefirst lateral alpha wrap pulley 28520 in a second opposite direction.Similarly, the second lateral alpha wrap pulley 28530 comprises a firstcircumferential groove 28532 and a second circumferential groove 28534.In the illustrated arrangement, the distal cable portion 28446 isreceived in the first circumferential groove 28532 and is attachedthereto and the third distal cable portion 28436 is received in thesecond circumferential groove 28534 and is attached thereto. Pulling onthe fourth distal cable portion 28446 will result in the rotation of thesecond alpha wrap pulley 28530 in the first direction and pulling thethird distal cable portion 28436 will result in the rotation of thesecond lateral alpha wrap pulley 28530 in the second opposite direction.In accordance with one aspect, the lateral alpha wrap pulleys 28520,28530 can rotate approximately three hundred thirty degrees. This rangeof rotational travel is in contrast to a normal pulley that may have arange of rotational travel that is less than one hundred eighty degreesof rotation.

Each of the first and second lateral alpha wrap pulleys 28520, 28530also comprise a corresponding spiral closure cam that is configured toapply closure motions to the anvil 26210. As can be seen in FIG. 126,the first lateral alpha wrap pulley 28520 includes a first spiralclosure cam 28526 and the second lateral alpha wrap pulley 28530 has asecond spiral closure cam 28536 thereon. The spiral closure cams 28526,28536 are configured to cammingly interact with corresponding anvilclosure arms 26234 on the anvil mounting portion 26230 of the anvil26210 to apply closure motions thereto. See FIG. 119. Rotation of thepulley unit 28510 in a first rotary direction will cause the spiralclosure cams 28526, 28536 to cam the anvil 26210 to the closed position.To open the anvil 26210, the pulley unit 28510 is rotated in oppositedirection to position the spiral closure cams 28526, 28536 in positionswherein the anvil 26210 can be pivoted open by an anvil spring (notshown).

In the illustrated arrangement, the proximal attachment disc 28240, theproximal-most annular disc member 28210P, annular proximal disc members28210A, 28210B, 28210C and anvil mounting bracket 26240 all includefourth articulation cable passages 28214 that are configured to permiteach of the distal cable portions 28416, 28426, 28436, and 28446 to passtherethrough. FIG. 127 illustrates the articulation rod 28424 slidablysupported in a corresponding axial groove 28146 in the distal spinesegment 28140 for axial travel therein. Each of the other articulationrods 28414, 28434, 28444 is similarly supported in axial grooves in thedistal spine segment 28140 as well as corresponding grooves in theproximal spine segment 28120.

Referring now to FIGS. 119 and 128-130, the distal cable portion 28416extends from the articulation rod 28414 through the articulation joint28200 and is looped around two redirect pulleys 28550, 28560 that aresupported on shafts 28502, 28512 that are rotatably mounted in theproximal end 26112 of the elongate channel 26110. The distal cableportion 28416 exits the articulation joint 28200 to be received withinthe first circumferential groove 28522 in the first lateral alpha wrappulley 28520 where it is secure therein. The distal cable portion 28426extends from the articulation rod 28424 through the articulation joint28200 to be looped around the redirect pulleys 28560, 28550 to bereceived within the second circumferential groove 28524 in the firstlateral alpha wrap pulley 28520 where it is secure therein.

In the illustrated example, distal cable portion 28436 extends from thearticulation rod 28434 through the articulation joint 28200 to bereceived within a corresponding circumferential groove 28534 in thesecond lateral alpha wrap pulley 28530 where it is secured therein. Inaddition, the distal cable portion 28446 extends from the articulationrod 28444 through the articulation joint 28200 to be received within acorresponding circumferential groove 28532 in the second lateral alphawrap pulley 28530 where it is secure therein.

In at least one example, to articulate the surgical end effector 26000relative to the elongate shaft assembly 28000 through a firstarticulation plane, the cable control system 25030 is actuated to pullon the distal cable portion 28426 and the distal cable portion 28446simultaneously with a same amount of tension being applied to eachdistal cable portion 28426, 28446. Because the distal cable portions28426, 28446 apply equal amounts of tension on both sides of the pulleyunit 28510, the pulley unit 28510 does not rotate. However, the pullingaction of the distal cable portions 28426, 28446 is translated throughthe articulation joint 28200 to the surgical end effector 26000 whichresults in the articulation of the articulation joint 28200 through afirst articulation plane. To articulate the surgical end effector 26000through a second plane of articulation that is transverse to the firstplane of articulation, the cable control system 25030 is actuated topull the distal cable portion 28436 and the distal cable portion 28446simultaneously with a same amount of tension being applied to eachdistal cable portion 28436, 28446. Because the distal cable portions28436, 28446 apply equal amounts of tension on both sides of the secondlateral alpha wrap pulley 25830 of the pulley unit 28510, the pulleyunit 28510 does not rotate. However, the pulling action of the distalcable portions 28436, 28446 is translated through the articulation joint28200 to the surgical end effector 26000 which results in thearticulation of the articulation joint 28200 in a second articulationplane.

The cable control system 25030 may also be used to control the openingand closing of the anvil 26210 in the following manner. As indicatedabove, when the spiral closure cams 28526 on the first lateral alphawrap pulley 28520 and the second lateral alpha wrap pulley 28530 are ina first position, the anvil 26210 may be pivoted to an open position byan anvil spring or springs (not shown) that are positioned in theproximal end 26112 of the elongate channel 26110 and are position tocontact the anvil mounting portion 26230 or anvil closure arms 26234 topivot the anvil 26210 to the open position. To close the anvil 26210from that position, the cable control system 25030 is actuated to pullthe distal cable portion 28416 and the distal cable portion 28446simultaneously with a same amount of tension being applied to eachdistal cable portion 28416 and 28446. These distal cable portions 28416,28446 will cause the pulley unit 28510 to rotate causing the spiralclosure cams 28526, 28536 to contact the anvil closure arms 26234 andcam the anvil 26210 to a closed position. It will be appreciated that byapplying equal amounts of tension into the distal cable portions 28416,28446, no moment is applied to the articulation joint 28200 becausethere are equal amounts of tension being applied on each side of theshaft axis SA. Such arrangement allows the jaw closure to be profiled asdesired. This cable-control system 25030 may allow for a faster closurewhen the anvil 26210 is fully open. The cable-control system 25030 canalso function as a lower speed/higher force generating closure mechanismfor clamping onto tissue. The present cable controlled system 25030 maynot produce the backlash that commonly occurs with othercable-controlled systems and thus can also be used to control thearticulation position of the end effector. The above-describedarticulation joint 28200 and cable controlled system 25030 canfacilitate multiple plane articulation while also supplying anadditional actuation motion to the surgical end effector 26000.

As was discussed above, many surgical end effectors employ a firingmember that is pushed distally through a surgical staple cartridge by anaxially movable firing beam. The firing beam is commonly attached to thefiring member in the center region of the firing member body. Thisattachment location can introduce an unbalance to the firing member asit is advanced through the end effector. Such unbalance can lead toundesirable friction between the firing member and the end effectorjaws. The creation of this additional friction may require anapplication of a higher firing force to overcome such friction as wellas can cause undesirable wear to portions of the jaws and/or the firingmember. An application of higher firing forces to the firing beam mayresult in unwanted flexure in the firing beam as it traverses thearticulation joint. Such additional flexure may cause the articulationjoint to de-articulate—particularly when the surgical end effector isarticulated at relatively high articulation angles. The surgicalinstrument 25010 employs a firing system 27000 that may address many ifnot all of such issues.

Referring now to FIGS. 133 and 134, in at least one embodiment, thefiring system 27000 comprises a firing member 27100 that includes avertically-extending firing member body 27112 that comprises a topfiring member feature 27120 and a bottom firing member feature 27130. Atissue cutting blade 27114 is attached to or formed in thevertically-extending firing member body 27112. In at least onearrangement, the top firing member feature 27120 comprises a top tubularbody 27122 that has a top axial passage 27124 extending therethrough.See FIG. 134. The bottom firing member feature 27130 comprises a bottomtubular body 27132 that has a bottom axial passage 27134 extendingtherethrough. In at least one arrangement, the top firing member feature27120 and the bottom firing member feature 27130 are integrally formedwith the vertically-extending firing member body 27112. In at least oneexample, the anvil body 26212 comprises an axially extending anvil slotthat has a cross-sectional shape that resembles a “keyhole” toaccommodate passage of the top firing member feature 27120 in thevarious manners discussed herein. Similarly, the elongate channel 26110comprises an axially extending channel slot that also has a keyholecross-sectional shape for accommodating passage of the bottom firingmember feature 27130 as described above.

In the illustrated arrangement, the firing system 27000 comprises anupper firing assembly 27200 that operably interfaces with the top firingmember feature 27120. The upper firing assembly 27200 includes an upperflexible outer tube or conduit 27210 that has a proximal end 27212 thatis fixed to an upper insert 27214 that is non-movably attached to theshaft spine assembly 28100. For example, the upper insert 27214 may bewelded to the shaft spine assembly 28100 or otherwise be attachedthereto by adhesive or other appropriate fastening means. The flexibleouter tube or conduit 27210 extends through upper passages 28216provided through the proximal attachment disc assembly 28240, theproximal-most annular disc member 28210P, the annular disc members28210A, 28210B, 28210C and the anvil mounting bracket 26240. A distalend 27216 of the flexible outer tube or conduit 27210 may be affixed tothe anvil mounting bracket 26240.

In the illustrated embodiment, the upper firing assembly 27200 furtherincludes an upper push rod 27220 that is slidably supported in acorresponding axial passage in the shaft spine assembly 28100. The upperfiring assembly 27200 further comprises an upper push coil 27230 that issupported in an inner flexible upper sleeve 27240 which extends throughthe upper flexible outer tube or conduit 27210. A proximal end 27232 ofthe upper push coil 27230 and a proximal end 27242 of the inner flexibleupper sleeve 27240 abut a distal end 27222 of the upper push rod 27220.The upper push coil 27230 is hollow and may comprise a coil spring thatis fabricated from Nitinol, titanium, stainless steel, etc. In otherarrangements, the upper push coil 27230 comprises a laser cut “hypotube”that essentially comprises a hollow tubular member with offset lasercuts therein which enable the hypotube to flex and bend while beingcapable of transmitting axial forces or motions. The inner flexibleupper sleeve 27240 may be fabricated from a polymer or similar materialand prevent tissue, fluid, and/or debris from infiltrating into theupper push coil 27230 which may hamper its ability to flex and bendduring articulation of the surgical end effector relative to theelongate shaft assembly.

As can be seen in FIG. 134, a distal end 27234 of the upper push coil27230 as well as a distal end 27244 of the inner flexible upper sleeve27240 abut a proximal end 27123 of the top tubular body 27122 or the topfiring member feature 27120. Also in the illustrated arrangement, theupper firing assembly further comprises an upper push coil cable 27250that extends through the hollow upper push coil 27230. The upper pushcoil cable 27250 comprises an upper cable proximal end 27252 that issecured to the distal end 27222 of the upper push rod 27220 and an uppercable distal end 27254 that is secured within the top axial passage27124 in the top tubular body 27122 of the top firing member feature27120 by an upper attachment lug 27256. The upper push coil cable 27250is held in tension between the top firing member feature 27120 an theupper push rod 27220 which serves to retain the distal end 27234 of theupper push coil 27230 as well as a distal end 27244 of the innerflexible upper sleeve 27240 in abutting contact with the proximal end27123 of the top tubular body 27122 of the top firing member feature27120 and the proximal end 27232 of the upper push coil 27230 and aproximal end 27242 of the inner flexible upper sleeve 27240 in abuttingcontact with the distal end 27222 of the upper push rod 27220.

In the illustrated example, the firing system 27000 further comprises alower firing assembly 27300 that operably interfaces with the bottomfiring member feature 27130. The lower firing assembly 27300 includes alower flexible outer tube or conduit 27310 that has a proximal end 27312that is fixed to a lower insert 27314 that is non-movably attached tothe shaft spine assembly 28100. For example, the lower insert 27314 maybe welded to the shaft spine assembly 28100 or otherwise be attachedthereto by adhesive or other appropriate fastening means. The lowerflexible outer tube or conduit 27310 extends through lower passages28218 provided in each of the proximal attachment disc assembly 28240,the proximal-most annular disc member 28210P, annular disc members28210A, 28210B, 28210C and anvil mounting bracket 26240. A distal end27316 of the flexible outer tube or conduit 27310 is affixed to theanvil mounting bracket 26240.

In the illustrated embodiment, the lower firing assembly 27300 furtherincludes a lower push rod 27320 that is slidably supported in acorresponding axial passage in the shaft spine assembly 28100. The lowerfiring assembly 27300 further comprises a lower push coil 27330 that issupported in an inner flexible lower sleeve 27340 which extends throughthe lower flexible outer tube or conduit 27310. A proximal end 27332 ofthe lower push coil 27330 and a proximal end 27342 of the inner flexiblelower sleeve 27340 abut a distal end 27322 of the lower push rod 27320.The lower push coil 27330 is hollow and may comprise a coil spring thatis fabricated from Nitinol, titanium, stainless steel, etc. In otherarrangements, the lower push coil 27330 comprises a laser cut hypotubethat essentially comprises a hollow tubular member with offset lasercuts therein which enable the hypotube to flex and bend. The innerflexible lower sleeve 27340 may be fabricated from a polymer or similarmaterial and prevent tissue, fluid, and/or debris from infiltrating intothe lower push coil 27330 which may hamper its ability to flex duringarticulation.

As can be seen in FIG. 134, a distal end 27334 of the lower push coil27330 as well as a distal end 27344 of the inner flexible lower sleeve27340 abut a proximal end 27133 of the bottom tubular body 27132 of thebottom firing member feature 27130. Also in the illustrated arrangement,the lower firing assembly 27300 further comprises a lower push coilcable 27350 that extends through the hollow lower push coil 27330. Thelower push coil cable 27350 comprises a lower cable proximal end 27352that is secured to the distal end 27322 of the lower push rod 27320 anda lower cable distal end 27354 that is secured within the bottom axialpassage 27134 in the bottom tubular body 27132 of the bottom firingmember feature 27130 by a lower attachment lug 27356. The lower pushcoil cable 27350 is held in tension between the bottom firing memberfeature 27130 an the lower push rod 27320 which serves to retain thedistal end 27334 of the lower push coil 27330 as well as a distal end27344 of the inner flexible lower sleeve 27340 in abutting contact withthe proximal end 27133 of the bottom tubular body 27132 of the bottomfiring member feature 27130 and the proximal end 27332 of the lower pushcoil 27330 and a proximal end 27342 of the inner flexible lower sleeve27340 in abutting contact with the distal end 27322 of the lower pushrod 27320.

In the illustrated arrangement, the firing system 27000 furthercomprises a differential drive assembly 27400 that is configured toaxially drive the upper firing assembly 27200 and the lower firingassembly 27300. Turning to FIGS. 136-139, in at least one arrangement, aproximal end 27224 of the upper push rod 27220 is coupled to a first orupper gear rack 27410 of the differential drive assembly 27400. As canbe seen in FIG. 136, the first or upper gear rack 27410 is slidablysupported in an upper proximal axial cavity 28122 in the proximal spinesegment 28120. Similarly, a proximal end 27324 of the lower push rod27320 is coupled to a second or lower gear rack 27420 that is supportedfor axial travel within a lower proximal axial cavity 28124 in theproximal spine segment 28120. The differential drive assembly 27400further comprises an axially movable carrier member 27430 that iscentrally disposed between the first or upper gear rack 27410 and thesecond or lower gear rack 27420 and is supported for axial travel withina proximal axial cavity 28126 in the proximal spine segment 28120. SeeFIG. 136. Still referring to FIGS. 136-139, a pinion gear 27432 ispivotally pinned to the axially movable carrier member 27430 such thatthe pinion gear 27432 is meshing engagement with the first or upper gearrack 27410 and the second or lower gear rack 27420. The axially movablecarrier member 27430 is driven axially within the proximal axial cavity28126 in the proximal spine segment 28120 by a firing drive actuator27440. See FIG. 137. In one arrangement, the firing drive actuator 27440comprises a firing drive gear rack 27442 that drivingly interfaces witha drive gear 27444 that is driven by a firing motor 27446 that may beoperably supported in or otherwise associated with the housing of thesurgical instrument 25010. In other arrangements, the firing driveactuator 27440 may be axially driven distally and proximally by acylinder arrangement or other suitable actuator interfacing therewith.As can be seen in FIGS. 137-139, the firing drive actuator 27440 may beattached to the axially movable carrier member 27430 by a pair of spacedcoupler pins 27448 that are attached to the firing drive actuator 27440and are received within corresponding axial slots 27434 in the axiallymovable carrier member 27430. Such arrangement permits some relativeaxial movement between the firing drive actuator 27440 and the axiallymovable carrier member 27430. For example, when the firing driveactuator 27440 is driven distally in the distal direction DD, theaxially movable carrier member 27430 will not move distally until thecoupler pins 27448 reach the distal ends of their corresponding axialslots 27434 at which point the axially movable carrier member 27430 willmove distally. Likewise, the when the firing drive actuator 27440 isdriven in the proximal direction PD, the axially movable carrier member27430 will not move proximally until the coupler pins 27448 reach theproximal ends of their corresponding axial slots 27434 at which pointthe axially movable carrier member 27430 will move proximally.

Surgical stapling devices need to apply a high force on the firingmember over a long displacement to form the staples and cut tissue.Transmitting that force through an articulated joint is especiallychallenging because it is difficult to redirect the forces in thedesired direction and withstand the loads applied to it. Thedifferential drive assembly 27400 described herein addresses and solvesmany, if not all of such challenges by employing two flexible outertubes or conduits 27210, 27310 to constrain the paths of the flexiblepush coils 27230, 27330, respectively. As described herein, the upperflexible outer tube or conduit 27210 surrounds a portion of the upperpush coil 27230 and the upper flexible outer tube or conduit 27310surrounds a portion of the lower push coil 27330. Each of the outertubes or conduits 27210, 27310 can bend but they also can resolve anaxial tensile load. The ability to bend allows for the firing memberforce to be redirected through the articulated joint, and the ability toresolve tension allows for it to change the direction in which the pushcoil goes. When the push coil 27230, 27330 is put in compression, theflexible outer tube or conduit 27210, 27310 is put in tension. The outertubes or conduits 27210, 27310 prevent the push coils 27230, 27330 frombuckling. The outer tubes 27210, 27310 are terminated in a manner toresolve the tensile loads. As described above, the distal end 27216 ofthe flexible outer tube or conduit 27210 and the distal end 27316 of theflexible outer tube or conduit 27310 are both affixed to the anvilmounting bracket 26240. The proximal end 27212 of the flexible outertube or conduit 27210 and the proximal end 27312 of the flexible outertube or conduit 27310 are both affixed to the shaft spine assembly28100. The pinion gear 27432 is in meshing engagement with the first orupper gear rack 27410 and the second or lower gear rack 27420 such thatwhen one of the racks 27410, 27420 moves in one axial direction, theother rack 27410, 27420 axially moves in an opposite direction. As canbe seen in FIGS. 138 and 139, during articulation, the pinion gear 27432rotates so the flexible outer tubes or conduits 27210, 27310 can move toaccount for the change in path length. However, when the firing driveactuator 27440 is driven in the distal direction DD, the axially movablecarrier member 27430 is actuated to push the push coils 27230, 27330distally through the outer tubes or conduits 27210, 27310 to fire (i.e.,drive the firing member 27100 distally) the tensile loads in the twoflexible outer tubes or conduits 27210, 27310 react against one anotherwithout any motion of the pinion gear 27432.

In accordance with one general aspect, the upper passages 28216 form anupper pathway 28221 (FIG. 117) through the articulation joint 28200.Similarly, the lower passages 28218 form a lower pathway 28223 throughthe articulation joint 28200. When the surgical end effector 26000 is inan unarticulated position (i.e., the surgical end effector is axiallyaligned with the elongate shaft assembly 28000 on the shaft axisSA—FIGS. 115, 117, 118), the upper pathway 28221 and the lower pathway28223 are parallel to each other. See FIG. 117. When the surgical endeffector 26000 is in an articulated position relative to the elongateshaft assembly 28000, the upper pathway 28221 and the lower pathway28223 are concentric to each other. See FIG. 116.

When the surgical end effector 26000 is in the unarticulated position,the firing system 27000 may be actuated to drive the firing member 27100from a starting position within the proximal end 26112 of the elongatechannel 26100 to an ending position within the distal end 26114 of theelongate channel 26110. When the surgical end effector 26000 is in theunarticulated position, and the firing system 27000 is actuated, thedifferential drive assembly 27400 drives the upper firing assembly 27200and the lower firing assembly 27300 equal axial distances in a sameaxial direction (i.e., the distal direction DD) to apply an upper axialdrive motion and a lower axial drive motion to the firing member 27100.The upper axial drive motion and the lower axial drive motion aresubstantially equal in magnitude which serves to distally advance thefiring member 27100 through the surgical end effector 26000 withoutbinding which might otherwise occur should the upper axial drive motionand the lower axial drive motions be different in magnitude. Similarly,when the surgical end effector 26000 is in an articulated positionrelative to the elongate shaft assembly 28000, the firing system 27000may be actuated to drive the firing member 27100 from the startingposition to the ending position. In such instances, the differentialdrive assembly 27400 is configured to permit the upper firing assembly27200 and the lower firing assembly 27300 to move in substantially equaldistances in opposite axial directions to accommodate the articulatedposition. The differential drive assembly 27400 may then apply an upperaxial drive motion and a lower axial drive motion that are equal to eachother to the firing member 27100. For example, depending upon thearticulated position of the surgical end effector 26000 relative to theelongate shaft assembly 28000, the upper firing assembly 27200, uponarticulation of the surgical end effector 26000, may be moved proximallya first distance and the lower firing assembly 27300 may be positionedrelative thereto distally a second distance that is substantially equalto the first distance by the pinion gear 27432. Thereafter, distalactuation of the firing drive actuator 27440 will cause the upper firingassembly 27200 and the lower firing assembly 27300 to apply an upperaxial drive motion and a lower axial drive motion that are equal to eachother to the firing member 27100. As used herein, when the carrier ismoved distally, the carrier may apply “axial control motions” to theupper firing assembly 27200 and the lower firing assembly 27300. Thus,when the surgical end effector 26000 is in an unarticulatedconfiguration, the carrier may apply equal amounts of axial controlmotions to the upper firing member 27200 and the lower firing member27300 in the same axial direction (distal direction DD) and when thesurgical end effector 26000 is in an articulated configuration, thecarrier may apply “other equal amounts” of axial control motions to theupper firing member 27200 and the lower firing member 27300 in the sameaxial direction (distal direction DD) to move the firing member 27100from the starting position to the ending position.

FIGS. 140-152 illustrate another surgical instrument 30010 that employsanother form of articulation joint 30200 for coupling a surgical endeffector 31000 to an elongate shaft assembly 32000. The elongate shaftassembly 32000 may be identical or very similar to various otherelongate shaft assemblies described herein. As can be seen in FIGS.140-143, the articulation joint 30200 comprises a proximal joint member30210 and a distal joint member 30250. The proximal joint member 30210is configured to be attached to a distal end of the elongate shaftassembly 32000 that is coupled to a housing or other portion of asurgical instrument. The distal joint member 30250 is configured to beattached to the surgical end effector 31000. For example, the distaljoint member 30250 may be attached to the elongate channel 31200 of thesurgical end effector 31000. The end effector 31000 may be identical orvery similar to various surgical end effectors disclosed herein.

As can be seen in FIGS. 143 and 150, the proximal joint member 30210comprises a proximal face 30212 that defines a proximal apex 30218.Similarly, the distal joint member 30250 comprises a distal face 30252that defines a distal apex 30254. See FIG. 151. The proximal jointmember 30210 and the distal joint member 30250 are pivotally retainedtogether with their respective apex portions 30218, 30254 in “rollinginter-engagement” by a linkage assembly 30300. As can be seen in FIGS.141-143, the linkage assembly 30300 comprises a first link 30310 and asecond link 30320. In the illustrated example, the first link 30310 andthe second link 30320 are coupled to the proximal joint member 30210 bya proximal cross pin assembly 30330. In accordance with one aspect, theproximal cross pin assembly 30330 comprises a first proximal cross pin30332 that defines a first proximal pivot axis FPPA. See FIG. 152. Aproximal end 30312 of the first link 30310 is configured to receive afirst proximal threaded fastener 30314 therethrough that is configuredto be threadably received in a first threaded hole 30334 in the firstproximal cross pin 30332. See FIG. 143. Likewise, a proximal end 30322of the second link 30320 is configured to receive a second proximalthreaded fastener 30324 therethrough that is configured to be threadablyreceived in a second threaded hole 30336 in the first proximal cross pin30332.

In at least one embodiment, the first proximal cross pin assembly 30330further comprises a second proximal cross pin 30340 that is rotatablyjournaled on the first proximal cross pin 30332. In one arrangement, thefirst proximal cross pin 30332 may comprise a first proximal bushing orlow friction sleeve 30338 that is configured to facilitate free rotationbetween the first proximal cross pin 30332 and the second proximal crosspin 30340. The second proximal cross pin 30340 defines a second proximalpivot axis SPPA that is transverse to the first proximal pivot axis FPPAand a shaft axis SA that is defined by the elongate shaft assembly32000. As can be seen in FIG. 143, the second proximal cross pin 30340is received within laterally aligned proximal pin openings 30220 in theproximal joint member 30210 to attach the linkage assembly 30300 to theproximal joint member 30210 such that the linkage assembly 30300 maypivot relative to the proximal joint member 30210 about the firstproximal pivot axis FPPA and the second proximal pivot axis SPPA.

In the illustrated example, the first link 30310 and the second link30320 are coupled to the distal joint member 30250 by a distal cross pinassembly 30350. In accordance with one aspect, the distal cross pinassembly 30350 comprises a first distal cross pin 30352 that defines afirst distal pivot axis FDPA. A distal end 30316 of the first link 30310is configured to receive a first distal threaded fastener 30318therethrough that is configured to be threadably received in a thirdthreaded hole 30354 in the first distal cross pin 30352. Likewise, adistal end 30326 of the second link 30320 is configured to receive asecond distal threaded fastener 30328 therethrough that is configured tobe threadably received in a fourth threaded hole 30356 in the firstdistal cross pin 30352.

In at least one embodiment, the first distal cross pin assembly 30350further comprises a second distal cross pin 30360 that is rotatablyjournaled on the first distal cross pin 30352. In one arrangement, thefirst distal cross pin 30352 may comprise a first proximal bushing orlow friction sleeve 30358 that is configured to facilitate free rotationbetween the first distal cross pin 30352 and the second distal cross pin30360. The second distal cross pin 30360 defines a second distal pivotaxis SDPA that is transverse to the first distal pivot axis FDPA and theshaft axis SA. As can be seen in FIG. 142, the second distal cross pin30360 is received within laterally aligned distal pin openings 30256 inthe distal joint member 30250 to attach the linkage assembly 30300 tothe distal joint member 30250 such that the linkage assembly 30300 maypivot relative to the distal joint member 30250 about the first distalpivot axis FDPA and the second distal pivot axis SDPA.

Turning now to FIG. 150, the proximal face 30212 of the proximal jointmember 30210 defines a proximal apex 30218 that comprises a plurality ofradially-spaced recessed regions 30222 formed thereon. In theillustrated arrangement, six total recessed regions 30222 are equallyspaced about a center 30219 of the proximal apex 30218. As can be seenin FIG. 151, the distal face 30252 of the distal joint member 30250comprises a total of six distal fins or protuberances 30262 that areequally spaced about a center 30255 of the distal apex 30254 such thateach fin 30262 is corresponds to one of the recessed regions 30222 whenthe surgical end effector is in an unarticulated position. For example,angle B may be approximately sixty degrees. See FIG. 151. Each of thefins 30262 and each of the recessed regions 30222 comprise rounded edgesconfigured to facilitate rolling inter-engagement between the proximalapex 30218 and the distal apex 30254 during articulation of the surgicalend effector 31000 relative to the elongate shaft assembly 32000. Suchrolling inter-engagement may be somewhat similar to the rollinginter-engagement between the teeth of intermeshing bevel gears, forexample such that the proximal apex 30218 and the distal apex 30254remain in engagement with each other during articulation of the surgicalend effector 31000.

Returning to FIG. 141, the surgical instrument 30010 also comprises anarticulation system 30500 that is configured to apply articulationmotions to the surgical end effector 31000 to articulate the surgicalend effector 31000 relative to the elongate shaft assembly 32000. In atleast one arrangement, the articulation system 30500 comprises fourarticulation cables 30510, 30520, 30530, and 30540 that extend throughthe elongate shaft assembly 32000. In the illustrated arrangement, thearticulation cables 30510, 30520, 30530, and 30540 pass through theproximal joint member 30210 and the distal joint member 30250 and aresecured to the surgical end effector 31000 in the various mannersdisclosed herein. The articulation cables 30510, 30520, 30530, and 30540operably interface with an articulation control system that is supportedin or otherwise associated with the housing of the surgical instrument300010. For example, as was discussed above, a proximal portion of eachcable 30510, 30520, 30530, and 30540 may be spooled on a correspondingrotary spool or cable-management system 2007 (FIG. 2) in the housingportion of the surgical instrument 30010 that is configured to payoutand retract each cable 30510, 30520, 30530, and 30540 in desiredmanners. The spools/cable management system may be motor powered ormanually powered (ratchet arrangement, etc.). FIGS. 140, 141, and144-146 illustrate the position of the articulation joint 30200 when thesurgical end effector is in an unarticulated position and FIGS. 142 and147-149 illustrate various positions of the articulation joint 30200when the surgical end effector has been articulated in various positionsrelative to the elongate shaft assembly 32000. The surgical instrument30010 may also employ a firing system 30600 of the various types andconstructions disclosed in detail herein to drive a firing member (notshown) within the surgical end effector 31000. For example, the proximaljoint member 30210 may be provided with an upper proximal firing memberpassage 30214 that is configured to accommodate passage of an upperflexible firing assembly 30610 therethrough. The upper flexible firingassembly 30610 may span across an area generally designated as 30700between the proximal face 30212 of the proximal joint member 30210 andthe distal face 30252 of the distal joint member 30250 to and slidablypass through an upper distal firing member passage 30257 in the distaljoint member 30250. Similarly, the proximal joint member 30210 isprovided with a lower proximal firing member passage 30216 that isconfigured to accommodate passage of a lower flexible firing assembly30620 member therethrough. The lower flexible firing assembly 30620spans area 30700 and is received in a lower distal firing member passage30259 in the distal joint member 30250. The upper flexible firingassembly 30610 and the lower flexible firing assembly 30620 operablyinterface with a firing member in the surgical end effector 31000. Theupper flexible firing assembly 30610 and the lower flexible firingassembly 30620 may be identical or very similar in construction to thevarious flexible firing member drive arrangements disclosed herein.

FIG. 153 illustrates another form of articulation joint 30200′ that isidentical in construction and operation to articulation joint 30200described above, except that the first link 30310 and the second link30320 are connected together by an annular ring 30380 that is located inthe area 30700 between the proximal face 30212 of the proximal jointmember 30210 and the distal face 30252 of the distal joint member 30250.In at least one arrangement, the annular ring 30380 comprises an outerdiameter which is equal to or less than an outer diameter of theproximal joint member 30210 and an outer diameter of the distal jointmember 30250. In one arrangement, for example, the outer diameter of thedistal joint member 30250 is equal to the outer diameter of the proximaljoint member 30210 which is equal to or less than the maximum outerdiameter of the elongate shaft assembly 32000. Thus, such arrangementpermits the surgical instrument 30010 to be inserted into a patientthrough a trocar cannula that can accommodate the maximum outer diameterof the elongate shaft assembly 32000. The annular ring 30380 may beparticularly advantageous as it may prevent tissue or a flexibleexterior joint cover (not shown) from potentially getting caught betweenthe joint components.

The articulation joints 30200, 30200′ utilize an outer linkage assembly30300 arrangement that connects the proximal cross pin assembly 30330and the distal cross pin assembly 30350 together and resolve torsionaland axial loads that are applied to the joint which may be particularimportant for resolving loads in the instrument during firing of thefiring member. Such joint arrangement further leaves space between theproximal joint member and distal joint member to accommodate additionalcomponents/features. As can be seen in the various Figures, the proximaljoint member and the distal joint member each are provided withclearance pockets/features/contours to accommodate the linkage assemblywhen the joint articulates.

FIGS. 154-156 illustrate another form of articulation joint 33000 thatmay be used to couple a surgical end effector of the various typesdisclosed herein to an elongate shaft assembly 34000 of a surgicalinstrument 33010. The elongate shaft assembly 34000 comprises a centralspine member 34100 (FIG. 155) that may be coupled to or otherwiseoperably interfaces with a housing (not shown) of the surgicalinstrument 33010. The elongate shaft assembly 34000 further comprises anouter tube member 34110 that is extends over the central spine member34100. In at least one form, the articulation joint 33000 comprises aproximal joint member 33100 that is attached to the central spine member34100 and a distal joint member 33300 that is attached to a surgical endeffector (not shown). For example, the distal joint member 33300 may beattached to an elongate channel of an endo-cutter arrangement in thevarious manners disclosed herein.

In the illustrated arrangement, the proximal joint member 33100comprises a first or right half segment 33100A and a second or left halfsegment 33100B that are attached to a distal end of the central spinemember 34100. The first half segment 33100A and the second half segment33100B may be attached to the central spine member 34100 or othersimilar component of the elongate shaft assembly 34000 by welding,adhesive, mechanical fasteners, pins, etc. In accordance with oneaspect, the surgical instrument 33010 comprises a firing system 35000that comprises a distal differential drive assembly 35100 and a proximaldifferential drive assembly 35500.

As can be seen in FIG. 156, the proximal joint member 33100 operablysupports the distal differential drive assembly 35100. In onearrangement, the distal differential drive assembly 35100 comprises anupper distal rack assembly 35110 that is supported for axial travelwithin the proximal joint member 33100. As can be seen in FIGS. 156,157, and 158, the upper distal rack assembly 35110 is supported inmeshing engagement with a distal differential gear 35130 that isrotatably supported on a pivot axle 35132 that is supported in theproximal joint member 33100. The upper distal rack assembly 35110 issupported for axial travel within the proximal joint member 33100. Thedistal differential drive assembly 35100 also comprises a lower distalrack assembly 35120 that is supported in meshing engagement with thedistal differential gear 35130 and is configured to travel axiallywithin the proximal joint member 33100.

In accordance with one aspect, the firing system 35000 further comprisesan upper flexible firing assembly 35300 and a lower flexible firingassembly 35400 that are configured to operably interface with a firingmember 35200. As can be seen in FIGS. 156 and 159, the firing member35200 includes a vertically-extending firing member body 35212 thatcomprises a top firing member feature 35220 and a bottom firing memberfeature 35230. A tissue cutting blade 35214 is attached to or formed inthe vertically-extending firing member body 35212. In at least onearrangement, the top firing member feature 35220 comprises a top finnedportion 35222 that has a top axial passage 35224 extending therethrough.The bottom firing member feature 35230 comprises a bottom finned portion35232 that has a bottom axial passage 35234 extending therethrough. Inat least one arrangement, the top firing member feature 35220 and thebottom firing member feature 35230 are integrally formed with thevertically-extending firing member body 35212. In at least one example,the anvil body comprises an axially extending anvil slot that isconfigured to accommodate passage of the top firing member feature 35220in the various manners discussed herein. Similarly, the elongate channelcomprises an axially extending channel slot that is configured toaccommodate passage of the bottom firing member feature 35230 asdescribed herein.

In one example, the upper flexible firing assembly 35300 comprises anupper flexible tube or conduit 35310 that has a proximal end 35312 thatis supported in a distal socket 3512 in the upper distal rack assembly35110 and is secured thereto by welding, adhesive, etc. The upperflexible tube or conduit 35310 extends through an upper opening 33218 inthe proximal joint member 33100 and spans across the articulation joint33000. The upper flexible tube or conduit 35310 comprises a distal end35314 that is received in an opening 33330 in the distal joint member33300 and is terminated or secured therein by welding, adhesive, etc.The upper flexible firing assembly 35300 further comprises an upper pushcoil 35320. The upper push coil 35320 is hollow and may comprise a coilspring that is fabricated from Nitinol, titanium, stainless steel, etc.In other arrangements, the upper push coil 35320 comprises a laser cuthypotube that essentially comprises a hollow tubular member with offsetlaser cuts or spiral cuts therein which enable the hypotube to flex andbend. The upper push coil 35320 may additionally be received within aninner flexible upper sleeve 35330 that may be fabricated from a polymeror similar material and prevent tissue, fluid, and/or debris frominfiltrating into the upper push coil 35320 which may hamper its abilityto flex and bend during articulation.

The upper push coil 35320 extends through the upper flexible tube 35310and through an axial passage in the upper distal rack 35110. An uppersupport beam 35140 is supported by the central spine member 34100 andhas an upper passage 35142 to constrain and permit passage of the upperpush coil 35320 therethrough. As can be seen in FIG. 159, a distal end35322 of the upper push coil 35320 as well as a distal end 35332 of theinner flexible upper sleeve 35330 abut a proximal end 35223 of the topfinned portion 35222 of the top firing member feature 35220. Also in theillustrated arrangement, the upper firing assembly 35300 furthercomprises an upper cable 35340 that extends through the hollow upperpush coil 35320. The upper cable 35340 comprises an upper cable distalend 35342 that is secured within the top axial passage 35224 in the topfinned portion 35222 of the top firing member feature 35220 by an upperattachment lug 35343.

Turning to FIGS. 156-161, the proximal differential drive assembly 35500comprises an upper gear rack 35510 that is slidably supported within thecentral spine member 34100. The proximal differential drive assembly35500 further comprises a lower proximal gear rack 35520 that issupported for axial travel within the central spine member 34100. Theproximal differential drive assembly 35500 also comprises an axiallymovable carrier member 35530 that is centrally disposed between theupper proximal gear rack 35510 and the lower proximal gear rack 35520and is supported for axial travel within the central spine member 34100.A proximal pinion gear 35532 is pivotally supported on a pin 35533 thatis mounted to the axially movable carrier member 35530 such that theproximal pinion gear 35532 is meshing engagement with the upper proximalgear rack 35510 and the lower proximal gear rack 35520. The axiallymovable carrier member 35530 is driven axially within an axial cavity inthe central spine member 34100 by a firing drive actuator 35540. As canbe seen in FIG. 160, the firing drive actuator 35540 comprises a firingdrive gear rack 35542 that drivingly interfaces with a drive gear 35544that is driven by a firing motor 35546 that may be operably supported inthe housing of the surgical instrument 33010. In other arrangements, thefiring drive actuator 35540 may be axially driven distally andproximally by a cylinder arrangement or other suitable actuatorinterfacing therewith. As can be seen in FIGS. 156 and 160, the firingdrive actuator 35540 may be attached to the axially movable carriermember 35530 by a pair of spaced coupler pins 35548.

In the illustrated arrangement, the upper proximal gear rack 35510further comprises an upper cable attachment feature 35512 that protrudestherefrom and is configured to slide within the upper passage 35142 inthe upper support beam 35140. In accordance with one aspect, the uppercable 35340 extends through the hollow upper push coil 35320 and aproximal end of the upper cable 35340 is secured to the upper cableattachment feature 35512. The upper cable 35340 is held in tensionbetween the top firing member feature 35220 and the upper cableattachment feature 35512 which serves to retain the distal end 35322 ofthe upper push coil 35320 as well as a distal end 35332 of the innerflexible upper sleeve 35330 in abutting contact with the proximal end35323 of the top finned portion 35222 of the top firing member feature35220 and the proximal end of the upper push coil 35320 and a proximalend of the inner flexible upper sleeve 35330 in abutting contact withthe distal end of the upper cable attachment feature 35512.

In one example, the lower flexible firing assembly 35400 comprises alower flexible tube or conduit 35410 that has a proximal end 35412 thatis supported in a distal socket 35122 in the lower distal rack 35120 andis secured thereto by welding, adhesive, etc. The lower flexible tube orconduit 35410 extends through a lower opening 33219 in the proximaljoint member 33100 and spans across the articulation joint 33000. Thelower flexible tube or conduit 35410 comprises a distal end 35414 thatis received in an opening 33340 in the distal joint member 33300 and isterminated or secured therein by welding, adhesive, etc. The lowerflexible firing assembly 35400 further comprises a lower push coil35420. The lower push coil 35420 is hollow and may comprise a coilspring that is fabricated from Nitinol, titanium, stainless steel, etc.In other arrangements, the lower push coil 35420 comprises a laser cuthypotube that essentially comprises a hollow tubular member with offsetlaser cuts or spiral cuts therein which enable the hypotube to flex andbend. The lower push coil 35420 may additionally be received within aninner flexible lower sleeve 35430 may be fabricated from a polymer orsimilar material and prevent tissue, fluid, and/or debris frominfiltrating into the lower push coil 35420 which may hamper its abilityto flex and bend during articulation.

The lower push coil 35420 extends through the lower flexible tube 35410and through an axial passage in the lower distal rack 35120. A lowersupport beam 35150 is supported by the central spine member 34100 andhas a lower passage 35152 to constrain and permit passage of the lowerpush coil 35420 therethrough. As can be seen in FIG. 159, a distal end35422 of the lower push coil 35420 as well as a distal end 35432 of theinner flexible lower sleeve 35430 abut a proximal end 35233 of thebottom finned portion 35232 of the bottom firing member feature 35230.Also in the illustrated arrangement, the lower flexible firing assembly35400 further comprises a lower cable 35440 that extends through thehollow lower push coil 35420. The lower cable 35440 comprises a lowercable distal end 35442 that is secured within the bottom axial passage35234 in the bottom finned portion 35232 of the bottom firing memberfeature 35230 by a lower attachment lug 35443. In accordance with oneaspect, the lower cable 35440 extends through the hollow lower push coil35420 and a distal end of the lower cable 35440 is secured to a lowercable attachment feature 35522 on the lower proximal gear rack 35520.The lower cable 35440 is held in tension between the bottom firingmember feature 35230 and the lower cable attachment feature 35522 whichserves to retain the distal end 35422 of the lower push coil 35420 aswell as a distal end 35332 of the inner flexible upper sleeve 35330 inabutting contact with the proximal end 35233 of the bottom finnedportion 35232 of the bottom firing member feature 35230 and the proximalend of the lower push coil 35420 and a proximal end of the innerflexible lower sleeve 35430 in abutting contact with the distal end ofthe lower cable attachment feature 35522.

Surgical stapling devices need to apply a high force on the firingmember over a long displacement to form the staples and cut tissue.Transmitting that force through an articulated joint is especiallychallenging because it is difficult to redirect the forces in thedesired direction and withstand the loads applied to it. The firingsystem 35000 described herein addresses and solves many, if not all ofsuch challenges by employing two flexible tubes 35310, 35410 toconstrain the paths of the push coils 35320, 35420, respectively. Asdescribed herein, the upper flexible tube 35310 surrounds the upper pushcoil 35320 and the lower flexible tube 35410 surrounds the lower pushcoil 35420. Each of the tubes 35310, 35410 can bend but they also canresolve an axial tensile load. See FIGS. 164 and 165. The ability tobend allows for the firing member force to be redirected through thearticulated joint, and the ability to resolve tension allows for it tochange the direction in which the push coil goes. When the push coil35320, 35420 is put in compression, the flexible tube 35310, 35410 isput in tension. The tube 35310, 35410 prevents the push coil 35320,35420 from buckling. To resolve the tensile loads the tubes 35310, 35410need to be terminated in a manner to resolve the loads. In theillustrated example, the respective distal ends 35314, 35414 of theflexible tubes 35310, 35410, respectively are secured to the distaljoint member 33300. The proximal ends 35312, 35412 of the flexible tubes35310, 35410 are secured to the upper distal rack assembly 35110 and thelower distal rack 35120, respectively. The distal differential gear35130 is in meshing engagement with each of the upper distal rackassembly 35110 and the lower distal rack 35120 such that when one of therack assemblies 35110, 35120 moves in one axial direction, the otherrack assembly 35110, 35120 would axially move in an opposite axialdirection. As can be seen in FIGS. 163-165, during articulation, thedistal differential gear 35130 rotates so the flexible tubes 35310,35410 can move to account for the change in path length. However, whenthe firing drive system is actuated to push the push coils 35320, 35420distally through the tubes 35310, 35410 to fire (i.e., drive the firingmember distally) the tensile loads in the two flexible tubes 35310,35410 react against one another without any motion of the distaldifferential gear 35130.

In accordance with one aspect, the upper flexible tube or conduit 35310forms an upper pathway that spans the articulation joint 33000 and thelower flexible tube or conduit 35410 forms a lower pathway that spansthe articulation joint 33000. The upper pathway supports the upper pushcoil 35320 for axial travel therethrough and the lower push coil 35420for axial travel therethrough. When the surgical end effector to whichthe articulation joint 33000 is attached is in an unarticulated position(i.e., the surgical end effector is axially aligned articulated with theelongate shaft assembly along the shaft axis) the upper pathway and thelower pathway are parallel. Stated another way, when the surgical endeffector is in an unarticulated position, an end effector axis isaxially aligned with the shaft axis and the upper pathway and the lowerpathway are parallel. When the surgical end effector is in anunarticulated position (i.e., the end effector axis is not axiallyaligned with the shaft axis), the upper pathway and the lower pathwayare concentric to each other. When the surgical end effector is in theunarticulated position, the proximal differential drive assembly isconfigured to drive the upper push coil 35320 and the lower push coil35420 equal distances in the same axial direction (distal direction DD)to apply an upper axial drive motion and a lower axial drive motion tothe firing member. The upper axial drive motion and the lower axialdrive motion are substantially equal in magnitude which serves todistally advance the firing member through the surgical end effectorwithout binding which might otherwise occur should the upper axial drivemotion and the lower axial drive motions be different in magnitude.Similarly, the when the surgical end effector is in an articulatedposition relative to the elongate shaft assembly, the proximaldifferential drive assembly is configured to permit the upper push coil35320 and the lower push coil 35420 to move in substantially equaldistances in opposite axial directions and thereafter apply an upperaxial drive motion and a lower axial drive motion that are equal to eachother to the firing member.

As can be seen in FIG. 156, the proximal joint member 33100 defines aproximal face 33200 that is configured to receive a spherical proximalend of 33410 of a central link member 33400. In the illustratedarrangement, the spherical proximal end 33410 is configured to bepivotally received in a proximal socket 33210 in the proximal face 33200of the proximal joint member 33100. The spherical proximal end 33410 ofthe central link member 33400 is retained within the proximal socket33210 by a proximal cross pin assembly 33500. In accordance with oneaspect, the proximal cross pin assembly 33500 comprises a first proximalcross pin 33510 that defines a first proximal pivot axis FPPA. The firstproximal cross pin 33510 is pivotally supported in a pair of attachmentlugs 33220 formed on the proximal face 33200 of the proximal jointmember 33100 and extends through two opposing arcuate slots 33412 topermit pivotal as well as rotational travel of the first proximal crosspin 33510 within the spherical proximal end 33410 of the central linkmember 33400. Stated another way, the spherical proximal end 33410 ofthe central link member 33400 is rotatable about the first proximalcross pin 33510 as well as pivotable through a proximal pivot angle PPAdefined by the arcuate slots 33412.

The proximal cross pin assembly 33500 further comprises a secondproximal cross pin 33520 that is rotatably journaled on the firstproximal cross pin 33510 to permit relative pivotal rotation between thefirst proximal cross pin 33510 and the second proximal cross pin 33520.The second proximal cross pin 33520 is pivotally supported within thespherical proximal end 33410 of the central link member 33400 anddefines a second proximal pivot axis SPPA. The first proximal pivot axisFPPA is transverse to the shaft axis SA. The second proximal pivot axisSPPA is transverse to the shaft axis SA as well as the first proximalpivot axis FPPA. The proximal cross pin assembly 33500 facilitatespivotal travel of the spherical proximal end 33410 of the central linkmember 33400 relative to the proximal joint member 33100 about the firstproximal pivot axis FPPA as well as the second proximal pivot axis SPPA.

In the illustrated arrangement, the distal joint member 33100 defines adistal face 33310 that is configured to receive a spherical distal end33420 of a central link member 33400. In the illustrated arrangement,the spherical distal end 33420 is configured to be pivotally received ina distal socket 33312 in the distal face 33310 of the distal jointmember 33300. The spherical distal end 33420 of the central link member33400 is retained within the distal socket 33312 by a distal cross pinassembly 33600. In accordance with one aspect, the distal cross pinassembly 33600 comprises a first distal cross pin 33610 that defines afirst distal pivot axis FDPA. The first distal cross pin 33610 ispivotally supported in a pair of attachment lugs 33314 formed on thedistal face 33312 of the distal joint member 33300 and extends throughtwo opposing arcuate slots 33422 to permit pivotal as well as rotationaltravel of the first distal cross pin 33610 within the spherical distalend 33420 of the central link member 33400. Stated another way, thespherical distal end 33420 of the central link member 33400 is rotatableabout the first distal cross pin 33610 as well as pivotable through adistal pivot angle DPA defined by the arcuate slots 33412.

The distal cross pin assembly 33600 further comprises a second distalcross pin 33620 that is rotatably journaled on the first distal crosspin 33610 to permit relative pivotal rotation between the first distalcross pin 33610 and the second distal cross pin 33620. The second distalcross pin 33620 is pivotally supported within the spherical distal end33420 of the central link member 33400 and defines a second distal pivotaxis SDPA. The first distal pivot axis FDPA is transverse to the shaftaxis SA. The second distal pivot axis SDPA is transverse to the shaftaxis SA as well as the first distal pivot axis FDPA. The distal crosspin assembly 33600 facilitates pivotal travel of the spherical distalend 33420 of the central link member 33400 relative to the distal jointmember 33300 about the first distal pivot axis FDPA as well as thesecond distal pivot axis SDPA.

In accordance with at least one aspect, the articulation joint 33000further comprises a flexible joint support assembly generally designatedas 33700 which provides flexible support between the proximal jointmember 33100 and the distal joint member 33200 during articulation aswell as to assist the articulation joint 33000 in returning to anunarticulated position (FIGS. 155-158). In at least one arrangement, theflexible joint support assembly 33700 comprises a series of flexiblemembers 33710, 33720, 33730, and 33740 that cross through a hollowcentral link portion 33430 that is attached to the spherical proximalend 33410 and the spherical distal end 33420 and extends therebetween.The flexible members 33710, 33720, 33730, and 33740 may comprise cablesor spring members that are fabricated from, for example, spring steel,stainless steel, Nitinol, titanium, etc. More particularly and withreference to FIG. 166, a first flexible member 33710 comprises a centralportion 33712 and a proximal end portion 33714 that is configured to bereceived in a corresponding attachment hole 33212 (FIG. 156) in thefirst or right half segment 33100A of the proximal joint member 33100and attached or secured therein. The first flexible member 33710 furthercomprises a distal end portion 33716 that is configured to be receivedin a corresponding slotted hole 33320 in the distal joint member 33300and be attached therein. In such arrangement, the central portion 33712of the first flexible member 33710 extends diagonally through the hollowcentral link portion 33430. The second flexible member 33720 comprises acentral portion 33722 and a proximal end portion 33724 that isconfigured to be received in a corresponding attachment hole 33214 (FIG.156) in the second or left segment 33100B of the proximal joint member33100 and be secured therein. The second flexible member 33720 furthercomprises a distal end portion 33726 that is configured to be receivedin a corresponding slotted hole 33322 in the distal joint member 33300and be secured therein. In such arrangement, the central portion 33722of the second flexible member 33720 extends diagonally through thehollow central link portion 33430. The third flexible member 33730comprises a central portion 33732 and a proximal end portion (not shown)that is configured to be inserted into a corresponding attachment hole(not shown) in the first or right segment 33100A of the proximal jointmember 33100 and be secured therein. The third flexible member 33730further comprises a distal end portion 33736 that is configured to bereceived in a corresponding slotted hole 33324 in the distal jointmember 33300 and be secured therein. In such arrangement, the centralportion 33732 of the third flexible member 33730 extends diagonallythrough the hollow central link portion 33430. The fourth flexiblemember 33740 comprises a central portion 33742 and a proximal endportion 33744 that is configured to be inserted into a correspondingattachment hole 33216 in the second or left segment 33100B of theproximal joint member 33100 and be secured therein. The fourth flexiblemember 33740 further comprises a distal end portion 33746 that isconfigured to be received in a corresponding slotted hole 33326 in thedistal joint member 33300 and be secured therein. In such arrangement,the central portion 33742 of the fourth flexible member 33740 extendsdiagonally through the hollow central link portion 33430.

The surgical instrument 33010 also comprises an articulation system33800 that is configured to apply articulation motions to the surgicalend effector to articulate the surgical end effector relative to theelongate shaft assembly 34000. In at least one arrangement, thearticulation system 33800 comprises four articulation cables 33810,33820, 33830, and 33840 that extend through the elongate shaft assembly34000. In the illustrated arrangement, the articulation cables 33810,33820, 33830, and 33840 pass through the proximal articulation jointmember 33100 and the distal articulation joint member 33300 and aresecured to the surgical end effector in the various manners disclosedherein. The articulation cables 33810, 33820, 33830, and 33840 operablyinterface with an articulation control system that is supported in or isotherwise associated with the housing of the surgical instrument 33010.For example, as was discussed above, a proximal portion of each cable33810, 33820, 33830, and 33840 may be spooled on a corresponding rotaryspool or cable-management system 2007 (FIG. 2) in the housing portion ofthe surgical instrument 330010 that is configured to payout and retracteach cable 33810, 33820, 33830, and 33840 in desired manners. Thespools/cable management system may be motor powered or manually powered(ratchet arrangement, etc.). FIGS. 154, 155, 157, 158, 162, and 167illustrate the position of the articulation joint 33000 when thesurgical end effector is in an unarticulated position and FIGS. 163 and169 illustrate various positions of the articulation joint 33000 whenthe surgical end effector has been articulated in various positionsrelative to the elongate shaft assembly.

The articulation joint 33000 comprises a spherical pitch and yaw jointthat is controlled by cables and is used for articulation of thesurgical end effector. The articulation joint comprises a doublespherical joint, meaning that it has a pair of joints that each canperform pitch and yaw. This arrangement creates redundancy in the jointas now there are two joints that can perform pitch and yaw. The flexiblejoint support assembly 33700 serves to constrain how each joint movesduring articulation so that the four degrees of freedom act as two. Theflexible joint support assembly 33700 ties the two spherical jointstogether such that if one rotates, the other one rotates the sameamount. When a joint rotates it applies tension in the cable that forcesthe other joint to rotate as well. Such joint arrangement has a verycompact form factor and very little backlash in the wrist design.

Example 1—A surgical instrument comprising a shaft assembly that definesa shaft axis and has a surgical end effector coupled thereto by anarticulation joint. The articulation joint comprises a proximal jointmember that is coupled to the shaft assembly and comprises a proximalface that defines a proximal apex. The articulation joint furthercomprises a distal joint member that is coupled to the surgical endeffector and comprises a distal face that defines a distal apex. Alinkage assembly is configured to retain the proximal apex in rollinginter-engagement with the distal apex. The linkage assembly comprises afirst link that is coupled to the proximal joint member for pivotaltravel relative thereto about a first proximal pivot axis that istransverse to the shaft axis and a second proximal pivot axis that istransverse to the first pivot axis and the shaft axis. The first link isfurther coupled to the distal joint member for pivotal travel relativethereto about a first distal pivot axis that is transverse to the shaftaxis and a second distal pivot axis that is transverse to the shaft axisand the first distal pivot axis. The linkage assembly further comprisesa second link that is coupled to the proximal joint member for pivotaltravel relative thereto about the first proximal pivot axis and thesecond proximal pivot axis. The second link is further coupled to thedistal joint member for pivotal travel relative thereto about the firstdistal pivot axis and the second distal pivot axis.

Example 2—The surgical instrument of Example 1, wherein the first linkis attached to the second link.

Example 3—The surgical instrument of Example 2, wherein the first linkis attached to the second link by an annular ring that extends betweenthe first link and the second link.

Example 4—The surgical instrument of Example 3, wherein the proximaljoint member comprises a proximal outer diameter and wherein the distaljoint member comprises a distal outer diameter that is equal to theproximal outer diameter. The annular ring comprises a ring outerdiameter that is equal to or less than the proximal outer diameter andthe distal outer diameter.

Example 5—The surgical instrument of Examples 1, 2, 3 or 4, furthercomprising a proximal cross-pin assembly that defines the first proximalpivot axis and the second proximal pivot axis. The surgical instrumentfurther comprises a distal cross-pin assembly that defines the firstdistal pivot axis and the second distal pivot axis.

Example 6—The surgical instrument of Example 5, wherein the proximalcross-pin assembly comprises a first proximal cross-pin and a secondproximal cross-pin. The second proximal cross-pin is rotatably journaledon the first proximal cross-pin to facilitate rotation of the firstproximal cross-pin relative to the second proximal cross-pin. The distalcross-pin assembly comprises a first distal cross-pin and a seconddistal cross-pin. The second distal cross-pin is rotatably journaled onthe first distal cross-pin to facilitate rotation of the first distalcross-pin relative to the second distal cross-pin.

Example 7—The surgical instrument of Example 6, wherein the first linkis removably coupled to the first proximal cross-pin and the firstdistal cross-pin. The second link is removably coupled to the firstproximal cross-pin and the first distal cross-pin.

Example 8—The surgical instrument of Examples 1, 2, 3, 4, 5, 6 or 7,wherein the proximal apex comprises a plurality of proximal engagementfeatures and the distal apex comprises a plurality of distal engagementfeatures that are in rolling engagement with the proximal engagementfeatures.

Example 9—The surgical instrument of Example 8, wherein the plurality ofproximal engagement features comprises a plurality of radiallyprojecting fin members, and wherein the distal engagement featurescomprises a plurality of radial recesses that are spaced between theplurality of radially projecting fin members.

Example 10—The surgical instrument of Examples 1, 2, 3, 4, 5, 6, 7, 8 or9, further comprising a plurality of flexible articulation actuatorsthat extend through the proximal joint member and the distal jointmember. Each flexible articulation member is coupled to the surgical endeffector and is configured to apply articulation motions thereto.

Example 11—A surgical instrument comprising a shaft assembly thatdefines a shaft axis and has a surgical end effector that defines an endeffector axis coupled thereto by an articulation joint. The articulationjoint is configured to facilitate articulation of the surgical endeffector relative to the shaft assembly between an unarticulatedposition in which the end effector axis is axially aligned with theshaft axis and articulated positions in which the end effector axis isnot axially aligned with the shaft axis. The articulation jointcomprises a proximal joint member that is coupled to the shaft assemblyand a distal joint member that is coupled to the surgical end effector.The articulation joint further comprises a central link member thatcomprises a proximal end that is coupled to the proximal joint memberfor pivotal travel relative thereto about a first proximal pivot axisthat is transverse to the shaft axis and a second proximal pivot axisthat is transverse to the first proximal pivot axis and the shaft axis.The central link further comprises a distal end that is coupled to thedistal joint member for pivotal travel relative thereto about a firstdistal pivot axis that is transverse to the shaft axis and a seconddistal pivot axis that is transverse to the first distal pivot axis andthe shaft axis.

Example 12—The surgical instrument of Example 11, wherein the proximalend of the central link member is coupled to the proximal joint memberby a proximal cross-pin assembly that defines the first proximal pivotaxis and the second proximal pivot axis. The distal end of said centrallink member is coupled to the distal joint member by a distal cross-pinassembly that defines the first distal pivot axis and the second distalpivot axis.

Example 13—The surgical instrument of Examples 11 or 12, wherein theproximal end of the central link member comprises a proximal sphericalmember that is rollably retained in a proximal socket in the proximaljoint member and the distal end of the central link member comprises adistal spherical member that is rollably retained in a distal socket inthe distal joint member.

Example 14—The surgical instrument of Examples 12 or 13, wherein theproximal cross-pin assembly comprises a first proximal cross-pin and asecond proximal cross-pin. The second proximal cross-pin is rotatablyjournaled on the first proximal cross-pin to facilitate rotation of thefirst proximal cross-pin relative to the second proximal cross-pin. Thedistal cross-pin assembly comprises a first distal cross-pin and asecond distal cross-pin. The second distal cross-pin is rotatablyjournaled on the first distal cross-pin to facilitate rotation of thefirst distal cross-pin relative to the second distal cross-pin.

Example 15—The surgical instrument of Example 14, wherein the firstproximal cross-pin is rotatably supported in the proximal joint memberand the second proximal cross-pin is rotatably supported in the proximalspherical member. The first distal cross-pin is rotatably supported inthe distal joint member and the second distal cross-pin is rotatablysupported in the distal spherical member.

Example 16—The surgical instrument of Examples 11, 12, 13, 14 or 15,further comprising a plurality of flexible articulation actuators thatextend through the proximal joint member and the distal joint member.Each flexible articulation member is coupled to the surgical endeffector and is configured to apply articulation motions thereto.

Example 17—The surgical instrument of Examples 11, 12, 13, 14, 15 or 16,wherein the central link member comprises a central link portion that iscoupled to the proximal spherical member and the distal spherical memberand extends therebetween.

Example 18—The surgical instrument of Example 17, further comprising aflexible joint support that surrounds the central link member and iscoupled to the proximal joint member and the distal joint member.

Example 19—The surgical instrument of Example 18, wherein the flexiblejoint support comprises a first flexible member that is coupled to theproximal joint member and the distal joint member. A second flexiblemember is coupled to the proximal joint member and the distal jointmember. A third flexible member is coupled to the proximal joint memberand the distal joint member and a fourth flexible member is coupled tothe proximal joint member and the distal joint member.

Example 20—The surgical instrument of Example 19, wherein each of thefirst flexible member, the second flexible member, the third flexiblemember, and the fourth flexible member pass through a central portion ofthe central link member.

As used in any aspect herein, the term “control circuit” may refer to,for example, hardwired circuitry, programmable circuitry (e.g., acomputer processor including one or more individual instructionprocessing cores, processing unit, processor, microcontroller,microcontroller unit, controller, digital signal processor (DSP),programmable logic device (PLD), programmable logic array (PLA), orfield programmable gate array (FPGA)), state machine circuitry, firmwarethat stores instructions executed by programmable circuitry, and anycombination thereof. The control circuit may, collectively orindividually, be embodied as circuitry that forms part of a largersystem, for example, an integrated circuit (IC), an application-specificintegrated circuit (ASIC), a system on-chip (SoC), desktop computers,laptop computers, tablet computers, servers, smart phones, etc.Accordingly, as used herein “control circuit” includes, but is notlimited to, electrical circuitry having at least one discrete electricalcircuit, electrical circuitry having at least one integrated circuit,electrical circuitry having at least one application specific integratedcircuit, electrical circuitry forming a general purpose computing deviceconfigured by a computer program (e.g., a general purpose computerconfigured by a computer program which at least partially carries outprocesses and/or devices described herein, or a microprocessorconfigured by a computer program which at least partially carries outprocesses and/or devices described herein), electrical circuitry forminga memory device (e.g., forms of random access memory), and/or electricalcircuitry forming a communications device (e.g., a modem, communicationsswitch, or optical-electrical equipment). Those having skill in the artwill recognize that the subject matter described herein may beimplemented in an analog or digital fashion or some combination thereof.

While several forms have been illustrated and described, it is not theintention of Applicant to restrict or limit the scope of the appendedclaims to such detail. Numerous modifications, variations, changes,substitutions, combinations, and equivalents to those forms may beimplemented and will occur to those skilled in the art without departingfrom the scope of the present disclosure. Moreover, the structure ofeach element associated with the described forms can be alternativelydescribed as a means for providing the function performed by theelement. Also, where materials are disclosed for certain components,other materials may be used. It is therefore to be understood that theforegoing description and the appended claims are intended to cover allsuch modifications, combinations, and variations as falling within thescope of the disclosed forms. The appended claims are intended to coverall such modifications, variations, changes, substitutions,modifications, and equivalents.

One or more components may be referred to herein as “configured to,”“configurable to,” “operable/operative to,” “adapted/adaptable,” “ableto,” “conformable/conformed to,” etc. Those skilled in the art willrecognize that “configured to” can generally encompass active-statecomponents and/or inactive-state components and/or standby-statecomponents, unless context requires otherwise.

Those skilled in the art will recognize that, in general, terms usedherein, and especially in the appended claims (e.g., bodies of theappended claims) are generally intended as “open” terms (e.g., the term“including” should be interpreted as “including but not limited to,” theterm “having” should be interpreted as “having at least,” the term“includes” should be interpreted as “includes but is not limited to,”etc.). It will be further understood by those within the art that if aspecific number of an introduced claim recitation is intended, such anintent will be explicitly recited in the claim, and in the absence ofsuch recitation no such intent is present. For example, as an aid tounderstanding, the following appended claims may contain usage of theintroductory phrases “at least one” and “one or more” to introduce claimrecitations. However, the use of such phrases should not be construed toimply that the introduction of a claim recitation by the indefinitearticles “a” or “an” limits any particular claim containing suchintroduced claim recitation to claims containing only one suchrecitation, even when the same claim includes the introductory phrases“one or more” or “at least one” and indefinite articles such as “a” or“an” (e.g., “a” and/or “an” should typically be interpreted to mean “atleast one” or “one or more”); the same holds true for the use ofdefinite articles used to introduce claim recitations.

In addition, even if a specific number of an introduced claim recitationis explicitly recited, those skilled in the art will recognize that suchrecitation should typically be interpreted to mean at least the recitednumber (e.g., the bare recitation of “two recitations,” without othermodifiers, typically means at least two recitations, or two or morerecitations). Furthermore, in those instances where a conventionanalogous to “at least one of A, B, and C, etc.” is used, in generalsuch a construction is intended in the sense one having skill in the artwould understand the convention (e.g., “a system having at least one ofA, B, and C” would include but not be limited to systems that have Aalone, B alone, C alone, A and B together, A and C together, B and Ctogether, and/or A, B, and C together, etc.). In those instances where aconvention analogous to “at least one of A, B, or C, etc.” is used, ingeneral such a construction is intended in the sense one having skill inthe art would understand the convention (e.g., “a system having at leastone of A, B, or C” would include but not be limited to systems that haveA alone, B alone, C alone, A and B together, A and C together, B and Ctogether, and/or A, B, and C together, etc.). It will be furtherunderstood by those within the art that typically a disjunctive wordand/or phrase presenting two or more alternative terms, whether in thedescription, claims, or drawings, should be understood to contemplatethe possibilities of including one of the terms, either of the terms, orboth terms unless context dictates otherwise. For example, the phrase “Aor B” will be typically understood to include the possibilities of “A”or “B” or “A and B.”

With respect to the appended claims, those skilled in the art willappreciate that recited operations therein may generally be performed inany order. Also, although various operational flow diagrams arepresented in a sequence(s), it should be understood that the variousoperations may be performed in other orders than those which areillustrated, or may be performed concurrently. Examples of suchalternate orderings may include overlapping, interleaved, interrupted,reordered, incremental, preparatory, supplemental, simultaneous,reverse, or other variant orderings, unless context dictates otherwise.Furthermore, terms like “responsive to,” “related to,” or otherpast-tense adjectives are generally not intended to exclude suchvariants, unless context dictates otherwise.

It is worthy to note that any reference to “one aspect,” “an aspect,”“an exemplification,” “one exemplification,” and the like means that aparticular feature, structure, or characteristic described in connectionwith the aspect is included in at least one aspect. Thus, appearances ofthe phrases “in one aspect,” “in an aspect,” “in an exemplification,”and “in one exemplification” in various places throughout thespecification are not necessarily all referring to the same aspect.Furthermore, the particular features, structures or characteristics maybe combined in any suitable manner in one or more aspects.

Any patent application, patent, non-patent publication, or otherdisclosure material referred to in this specification and/or listed inany Application Data Sheet is incorporated by reference herein, to theextent that the incorporated materials is not inconsistent herewith. Assuch, and to the extent necessary, the disclosure as explicitly setforth herein supersedes any conflicting material incorporated herein byreference. Any material, or portion thereof, that is said to beincorporated by reference herein, but which conflicts with existingdefinitions, statements, or other disclosure material set forth hereinwill only be incorporated to the extent that no conflict arises betweenthat incorporated material and the existing disclosure material.

In summary, numerous benefits have been described which result fromemploying the concepts described herein. The foregoing description ofthe one or more forms has been presented for purposes of illustrationand description. It is not intended to be exhaustive or limiting to theprecise form disclosed. Modifications or variations are possible inlight of the above teachings. The one or more forms were chosen anddescribed in order to illustrate principles and practical application tothereby enable one of ordinary skill in the art to utilize the variousforms and with various modifications as are suited to the particular usecontemplated. It is intended that the claims submitted herewith definethe overall scope.

The surgical instrument systems described herein have been described inconnection with the deployment and deformation of staples; however, theembodiments described herein are not so limited. Various embodiments areenvisioned which deploy fasteners other than staples, such as clamps ortacks, for example. Moreover, various embodiments are envisioned whichutilize any suitable means for sealing tissue. For instance, an endeffector in accordance with various embodiments can comprise electrodesconfigured to heat and seal the tissue. Also, for instance, an endeffector in accordance with certain embodiments can apply vibrationalenergy to seal the tissue.

Many of the surgical instrument systems described herein are motivatedby an electric motor; however, the surgical instrument systems describedherein can be motivated in any suitable manner. In various instances,the surgical instrument systems described herein can be motivated by amanually-operated trigger, for example. In certain instances, the motorsdisclosed herein may comprise a portion or portions of a roboticallycontrolled system. Moreover, any of the end effectors and/or toolassemblies disclosed herein can be utilized with a robotic surgicalinstrument system. U.S. patent application Ser. No. 13/118,241, entitledSURGICAL STAPLING INSTRUMENTS WITH ROTATABLE STAPLE DEPLOYMENTARRANGEMENTS, now U.S. Pat. No. 9,072,535, for example, disclosesseveral examples of a robotic surgical instrument system in greaterdetail.

The entire disclosures of:

U.S. Pat. No. 5,403,312, entitled ELECTROSURGICAL HEMOSTATIC DEVICE,which issued on Apr. 4, 1995;

U.S. Pat. No. 7,000,818, entitled SURGICAL STAPLING INSTRUMENT HAVINGSEPARATE DISTINCT CLOSING AND FIRING SYSTEMS, which issued on Feb. 21,2006;

U.S. Pat. No. 7,422,139, entitled MOTOR-DRIVEN SURGICAL CUTTING ANDFASTENING INSTRUMENT WITH TACTILE POSITION FEEDBACK, which issued onSep. 9, 2008;

U.S. Pat. No. 7,464,849, entitled ELECTRO-MECHANICAL SURGICAL INSTRUMENTWITH CLOSURE SYSTEM AND ANVIL ALIGNMENT COMPONENTS, which issued on Dec.16, 2008;

U.S. Pat. No. 7,670,334, entitled SURGICAL INSTRUMENT HAVING ANARTICULATING END EFFECTOR, which issued on Mar. 2, 2010;

U.S. Pat. No. 7,753,245, entitled SURGICAL STAPLING INSTRUMENTS, whichissued on Jul. 13, 2010;

U.S. Pat. No. 8,393,514, entitled SELECTIVELY ORIENTABLE IMPLANTABLEFASTENER CARTRIDGE, which issued on Mar. 12, 2013;

U.S. patent application Ser. No. 11/343,803, entitled SURGICALINSTRUMENT HAVING RECORDING CAPABILITIES, now U.S. Pat. No. 7,845,537;

U.S. patent application Ser. No. 12/031,573, entitled SURGICAL CUTTINGAND FASTENING INSTRUMENT HAVING RF ELECTRODES, filed Feb. 14, 2008;

U.S. patent application Ser. No. 12/031,873, entitled END EFFECTORS FORA SURGICAL CUTTING AND STAPLING INSTRUMENT, filed Feb. 15, 2008, nowU.S. Pat. No. 7,980,443;

U.S. patent application Ser. No. 12/235,782, entitled MOTOR-DRIVENSURGICAL CUTTING INSTRUMENT, now U.S. Pat. No. 8,210,411;

U.S. patent application Ser. No. 12/235,972, entitled MOTORIZED SURGICALINSTRUMENT, now U.S. Pat. No. 9,050,083;

U.S. patent application Ser. No. 12/249,117, entitled POWERED SURGICALCUTTING AND STAPLING APPARATUS WITH MANUALLY RETRACTABLE FIRING SYSTEM,now U.S. Pat. No. 8,608,045;

U.S. patent application Ser. No. 12/647,100, entitled MOTOR-DRIVENSURGICAL CUTTING INSTRUMENT WITH ELECTRIC ACTUATOR DIRECTIONAL CONTROLASSEMBLY, filed Dec. 24, 2009, now U.S. Pat. No. 8,220,688;

U.S. patent application Ser. No. 12/893,461, entitled STAPLE CARTRIDGE,filed Sep. 29, 2012, now U.S. Pat. No. 8,733,613;

U.S. patent application Ser. No. 13/036,647, entitled SURGICAL STAPLINGINSTRUMENT, filed Feb. 28, 2011, now U.S. Pat. No. 8,561,870;

U.S. patent application Ser. No. 13/118,241, entitled SURGICAL STAPLINGINSTRUMENTS WITH ROTATABLE STAPLE DEPLOYMENT ARRANGEMENTS, now U.S. Pat.No. 9,072,535;

U.S. patent application Ser. No. 13/524,049, entitled ARTICULATABLESURGICAL INSTRUMENT COMPRISING A FIRING DRIVE, filed on Jun. 15, 2012,now U.S. Pat. No. 9,101,358;

U.S. patent application Ser. No. 13/800,025, entitled STAPLE CARTRIDGETISSUE THICKNESS SENSOR SYSTEM, filed on Mar. 13, 2013, now U.S. Pat.No. 9,345,481;

U.S. patent application Ser. No. 13/800,067, entitled STAPLE CARTRIDGETISSUE THICKNESS SENSOR SYSTEM, filed on Mar. 13, 2013, now U.S. PatentApplication Publication No. 2014/0263552;

U.S. Patent Application Publication No. 2007/0175955, entitled SURGICALCUTTING AND FASTENING INSTRUMENT WITH CLOSURE TRIGGER LOCKING MECHANISM,filed Jan. 31, 2006; and

U.S. Patent Application Publication No. 2010/0264194, entitled SURGICALSTAPLING INSTRUMENT WITH AN ARTICULATABLE END EFFECTOR, filed Apr. 22,2010, now U.S. Pat. No. 8,308,040, are hereby incorporated by referenceherein.

Although various devices have been described herein in connection withcertain embodiments, modifications and variations to those embodimentsmay be implemented. Particular features, structures, or characteristicsmay be combined in any suitable manner in one or more embodiments. Thus,the particular features, structures, or characteristics illustrated ordescribed in connection with one embodiment may be combined in whole orin part, with the features, structures or characteristics of one or moreother embodiments without limitation. Also, where materials aredisclosed for certain components, other materials may be used.Furthermore, according to various embodiments, a single component may bereplaced by multiple components, and multiple components may be replacedby a single component, to perform a given function or functions. Theforegoing description and following claims are intended to cover allsuch modification and variations.

The devices disclosed herein can be designed to be disposed of after asingle use, or they can be designed to be used multiple times. In eithercase, however, a device can be reconditioned for reuse after at leastone use. Reconditioning can include any combination of the stepsincluding, but not limited to, the disassembly of the device, followedby cleaning or replacement of particular pieces of the device, andsubsequent reassembly of the device. In particular, a reconditioningfacility and/or surgical team can disassemble a device and, aftercleaning and/or replacing particular parts of the device, the device canbe reassembled for subsequent use. Those skilled in the art willappreciate that reconditioning of a device can utilize a variety oftechniques for disassembly, cleaning/replacement, and reassembly. Use ofsuch techniques, and the resulting reconditioned device, are all withinthe scope of the present application.

The devices disclosed herein may be processed before surgery. First, anew or used instrument may be obtained and, when necessary, cleaned. Theinstrument may then be sterilized. In one sterilization technique, theinstrument is placed in a closed and sealed container, such as a plasticor TYVEK bag. The container and instrument may then be placed in a fieldof radiation that can penetrate the container, such as gamma radiation,x-rays, and/or high-energy electrons. The radiation may kill bacteria onthe instrument and in the container. The sterilized instrument may thenbe stored in the sterile container. The sealed container may keep theinstrument sterile until it is opened in a medical facility. A devicemay also be sterilized using any other technique known in the art,including but not limited to beta radiation, gamma radiation, ethyleneoxide, plasma peroxide, and/or steam.

While this invention has been described as having exemplary designs, thepresent invention may be further modified within the spirit and scope ofthe disclosure. This application is therefore intended to cover anyvariations, uses, or adaptations of the invention using its generalprinciples.

What is claimed is:
 1. A surgical instrument, comprising: a shaftassembly that defines a shaft axis; a surgical end effector coupled tosaid shaft assembly by an articulation joint configured to facilitatearticulation of said surgical end effector relative to said shaftassembly between an unarticulated position and articulated positions,wherein said articulation joint comprises: a proximal joint membercoupled to said shaft assembly, wherein said proximal joint membercomprises a proximal face that defines a proximal apex; a distal jointmember coupled to said surgical end effector, wherein said distal jointmember comprises a distal face that defines a distal apex; and a linkageassembly configured to retain said proximal apex in rollinginter-engagement with said distal apex, wherein said linkage assemblycomprises: a first link coupled to said proximal joint member forpivotal travel relative thereto about a first proximal pivot axis thatis transverse to the shaft axis and a second proximal pivot axis that istransverse to the first pivot axis and the shaft axis, and wherein saidfirst link is coupled to said distal joint member for pivotal travelrelative thereto about a first distal pivot axis that is transverse tothe shaft axis and a second distal pivot axis that is transverse to theshaft axis and the first distal pivot axis; and a second link coupled tosaid proximal joint member for pivotal travel relative thereto about thefirst proximal pivot axis and the second proximal pivot axis, andwherein said second link is coupled to said distal joint member forpivotal travel relative thereto about the first distal pivot axis andthe second distal pivot axis.
 2. The surgical instrument of claim 1,wherein said first link is attached to said second link.
 3. The surgicalinstrument of claim 2, wherein said first link is attached to saidsecond link by an annular ring that extends between said first link andsaid second link.
 4. The surgical instrument of claim 3, wherein saidproximal joint member comprises a proximal outer diameter, wherein saiddistal joint member comprises a distal outer diameter that is equal tothe proximal outer diameter and wherein said annular ring comprises aring outer diameter that is equal to or less than the proximal outerdiameter and the distal outer diameter.
 5. The surgical instrument ofclaim 1, further comprising: a proximal cross-pin assembly, wherein saidproximal cross-pin assembly defines the first proximal pivot axis andthe second proximal pivot axis; and a distal cross-pin assembly, whereinsaid distal cross-pin assembly defines the first distal pivot axis andthe second distal pivot axis.
 6. The surgical instrument of claim 5,wherein said proximal cross-pin assembly comprises: a first proximalcross-pin; and a second proximal cross-pin rotatably journaled on saidfirst proximal cross-pin to facilitate rotation of said first proximalcross-pin relative to said second proximal cross-pin, and wherein saiddistal cross-pin assembly comprises: a first distal cross-pin; and asecond distal cross-pin rotatably journaled on said first distalcross-pin to facilitate rotation of said first distal cross-pin relativeto said second distal cross-pin.
 7. The surgical instrument of claim 6,wherein said first link is removably coupled to said first proximalcross-pin and said first distal cross-pin, and wherein said second linkis removably coupled to said first proximal cross-pin and said firstdistal cross-pin.
 8. The surgical instrument of claim 1, wherein saidproximal apex comprises a plurality of proximal engagement features, andwherein said distal apex comprises a plurality of distal engagementfeatures that are in rolling engagement with said proximal engagementfeatures.
 9. The surgical instrument of claim 8, wherein said pluralityof proximal engagement features comprises a plurality of radiallyprojecting fin members, and wherein said distal engagement featurescomprises a plurality of radial recesses spaced between said pluralityof radially projecting fin members.
 10. The surgical instrument of claim1, further comprising a plurality of flexible articulation actuatorsextending through said proximal joint member and said distal jointmember, wherein each said flexible articulation member is coupled tosaid surgical end effector and is configured to apply articulationmotions thereto.
 11. A surgical instrument, comprising: a shaftassembly, wherein said shaft assembly defines a shaft axis; a surgicalend effector, wherein said surgical end effector defines an end effectoraxis, wherein said surgical end effector is coupled to said shaftassembly by an articulation joint configured to facilitate articulationof said surgical end effector relative to said shaft assembly between anunarticulated position in which the end effector axis is axially alignedwith the shaft axis and articulated positions in which the end effectoraxis is not axially aligned with the shaft axis, and wherein saidarticulation joint comprises: a proximal joint member coupled to saidshaft assembly; a distal joint member coupled to said surgical endeffector; and a central link member comprising: a proximal end coupledto said proximal joint member for pivotal travel relative thereto abouta first proximal pivot axis that is transverse to the shaft axis and asecond proximal pivot axis that is transverse to the first proximalpivot axis and the shaft axis; and a distal end coupled to said distaljoint member for pivotal travel relative thereto about a first distalpivot axis that is transverse to the shaft axis and a second distalpivot axis that is transverse to the first distal pivot axis and theshaft axis.
 12. The surgical instrument of claim 11, wherein saidproximal end of said central link member is coupled to said proximaljoint member by a proximal cross-pin assembly, wherein said proximalcross-pin assembly defines the first proximal pivot axis and the secondproximal pivot axis, and wherein said distal end of said central linkmember is coupled to said distal joint member by a distal cross-pinassembly, and wherein said distal cross-pin assembly defines the firstdistal pivot axis and the second distal pivot axis.
 13. The surgicalinstrument of claim 12, wherein said proximal end of said central linkmember comprises a proximal spherical member rollably retained in aproximal socket in said proximal joint member, and wherein said distalend of said central link member comprises a distal spherical memberrollably retained in a distal socket in said distal joint member. 14.The surgical instrument of claim 13, wherein said proximal cross-pinassembly comprises: a first proximal cross-pin; and a second proximalcross-pin rotatably journaled on said first proximal cross-pin tofacilitate rotation of said first proximal cross-pin relative to saidsecond proximal cross-pin, and wherein said distal cross-pin assemblycomprises: a first distal cross-pin; and a second distal cross-pinrotatably journaled on said first distal cross-pin to facilitaterotation of said first distal cross-pin relative to said second distalcross-pin.
 15. The surgical instrument of claim 14, wherein said firstproximal cross-pin is rotatably supported in said proximal joint memberand said second proximal cross-pin is rotatably supported in saidproximal spherical member, and wherein said first distal cross-pin isrotatably supported in said distal joint member and said second distalcross-pin is rotatably supported in said distal spherical member. 16.The surgical instrument of claim 11, further comprising a plurality offlexible articulation actuators extending through said proximal jointmember and said distal joint member, and wherein each said flexiblearticulation member is coupled to said surgical end effector and isconfigured to apply articulation motions thereto.
 17. The surgicalinstrument of claim 13, wherein said central link member comprises acentral link portion coupled to said proximal spherical member and saiddistal spherical member and extends therebetween.
 18. The surgicalinstrument of claim 17, further comprising a flexible joint supportsurrounding said central link member and coupled to said proximal jointmember and said distal joint member.
 19. The surgical instrument ofclaim 18, wherein said flexible plurality of flexible joint supportcomprises: a first flexible member coupled to said proximal joint memberand said distal joint member; a second flexible member coupled to saidproximal joint member and said distal joint member; a third flexiblemember coupled to said proximal joint member and said distal jointmember; and a fourth flexible member coupled to said proximal jointmember and said distal joint member.
 20. The surgical instrument ofclaim 19, wherein each of said first flexible member, said secondflexible member, said third flexible member, and said fourth flexiblemember pass through a central portion of said central link member.